I've been on a huge loss spree as well so I switched to casual only matches as you still earn fight money and xp. I'll practice on there before moving back to ranked. 

Beware though. There are a lot of really good fighters with low lp in casual only. You think they are rubbish due to their low lp score and Rookie rank. Some of them are by far the best I've come across. 

Usually I test my way through this. But for frame traps and punishes, I prefer to look at frame data since testing it against the training dummy feels like a waste of time.
For example here I see that Chun's back+HP is +2 on block.


I had no idea. I assumed it would be -1 or something. From this I can already see which moves can be used as a frame trap instead of testing each individual move and recording the dummy to press various buttons.
For example, this means even her st.mp (5f startup) can be used as a frame trap after a blocked back+HP and grant you a counterhit no matter what button the opponent presses, because in this game, like in SF3, and unlike SF4, if two normals collide at the exact same frame, the stronger button will beat out the weaker button cleanly. And since her st.mp can combo into cr.mk> special/critical art, it makes this move very powerful even on block.

And I infered all that as soon as I saw the number 2 next to it on the framedata, while reading it on my phone while on a train. It would take time to test all these things, and in SFV you also need to know what a move is after V-trigger cancel on hit or block as well. And knowing how much stun or V-gauge a move builds can help you decide to use one move over another. So framedata helps a lot with saving you time. Then once you have an idea of what you want to do with it, you go into training mode and pratice.

The Prima Games guide is excellent by the way. Highly recommend it. It has all the info you can imagine, except for hit/hurt boxes.

Regarding punishes, when it comes to how unsafe your own move is on block, it can be hard to see if they're unsafe at all if it's only -3 or something, unless your opponent properly punishes it. But what's also important to know is how punishable it is. If your move is only -3 on block, you can't get punished very hard because all your opponent can do to punish you is hit you with a light punch or kick, which in this game for most characters can't combo into mediums. However, depending on how negative you are on block after your attack, the punish your opponent can make if they block your move can be much more severe. And the difference between being heavy punch/kick into Critical Art punished can be as little as one frame. Knowing the difference will help you better gauge your risk vs reward decision making.

For example, if Move A can only be punished with 150 damage, and Move B can be punished with 450 damage, I may chose to go with Move A to be safe. Or I can chose to take the risk of going with Move B, because if I land it, I know it will lead into a combo that will kill my opponent, whereas Move A will not.
Or, if I'm already at such a low health that either option will get me killed on block, I might as well go for the bigger rewarding attack. Unless that's what my opponent expects and is ready fort it..

Anyway my point is this. 1 single frame can make a huge difference, and that's 1/60th of a second, whcih is impossible to discern with your eyes.
Even if your opponent tries to punish one of your moves and fails, you can't be 100% certain that it's safe because they may have pressed the button too late, whether they are the CPU or a human opponent. Ther only way to be sure is to test against the training dummy in training mode, or have a friend help you control it for this specific purpose. Or read the framedata. Which saves you a lot of time not having to test a lot of things manually.

Then we have frame traps. Just knowing whether a move is safe on block or not isn't enough to know if you can use it as a frametrap.
For example, if your attack is -1 on block (meaning you will recover from your animation 1 frame later than your opponent recovers from their block stun animation), if you block after your attack, you will be safe. However, if you both press a light button immediately after this, you will get hit with a counter hit. But if you are +1 after your attack is blocked, the situation is reversed. You will hit your opponent with a counterhit instead, if you both press a button.
And if you are +2, as with the example of Chun Li above, you can even use a medium punch instead of a light one, and still beat out your opponents move for even more damage and higher combo potential. And that's the difference 1 single frame can do.

"I can assure you, you will be punished."? If you mean that you will always be punished by an opponent if you are in a punishable state, then that's not the case 100% of the time. Both players and CPU fail to do this from time to time. Which can be missleading. Over time though, you will notice.
However, that was only a small part of my point. It wasn't just about if something is safe or not, but how safe or punishable something is. It sounds like you either didn't read, or understand my post above. If it's the former, then please read through it again. Or is it that you don't quite understand how frame data or frametraps work? If so let me know and I'll try my best to explain it.

I'll try a simpler explanation here: It's not just about whether or not you will be punished, but how much of an advantage or disadvantage it leaves you, as the difference one single frame can open up for a lot of different possibilities. It can make the difference of punishable (slightly and severely) or safe, at a disadvantage or at an advantage (frametrap setup), and how strong of a button you can use for that frametrap.

The human eye can't discern the difference of 1/60th of a second. So a few frame differences need to be properly tested.
And regarding what you said about normals startup being "mostly within range of each other", while true in some cases, again, one single frame difference can change a lot. And an example of the complete opposite is again Chun Li's Back + HP. In this game it's +2 on block. In Street Fighter 4 (close HP), it was -7 on block. And even -2 on hit. That's an astronomical change to the exact same move.
While we can assume that most lights are either 3 or 4 fr, and mediums are around 4-5f, even if you want to take a guess rather than be sure, what they are on recovery and block doesn't follow the same logical pattern.
But again, simply knowing whether something is safe or unsafe is just one part of it. Knowing exactly how many frames of advantage/disadvantage will give you new options. And in order to discern exactly how many frames that is, requires testing, because you can't know, or trust, that your opponent will always press their fastest 3frame move after block without delaying it for a single frame. Whether on purpose or not.

So you're saying the eye isn't fast enough to discern the difference, yet your fingers are fast enough to react?  You can catch when your animation has ended visually.

I'm saying if you play often you're going to get punished for leaving yourself open.  My friend mains Birdie, he figured out when I leave Cammy open and has been punishing me.  So I had to adapt.  He didn't need frame data to find out Cammy's frame traps.  I also needed to get punished to figure out Cammy's frame traps.  Then we both adapted.  Same with Laura.  I needed to get smacked around a few times to figure out what's safe and what's not safe.  Even before.  There was no frame data to analyze.  Everyone picked it up as they played.  You can tell when an animation's about to end and when it's safe to attack.