It's not about cool or not it's about software and games application that used and maximize the utilization of SSD and build based on that tech. Non of games that been made are made on SSD in mind.

I have been use SSD as well on PC for  quiet long and until these days all games is just load on normal loading screen , what make difference is just using ssd is just more faster . 

What we have in the video is they get rid the loading screen and moment. All games from PS5 will be made with this in mind. Thanks to console that push this old tech to become mainstream. 

Now bring LoD to PS5

I'd imagine Sony may make this a mandatory thing.  Or it may just be something devs don't have to do anything different to take advantage of.  Now, the only question is, will MS copy this approach or will they stick with HDD only.  If they don't have this tech, will they try to force some ridiculous parity clause so that every comparison video doesn't show the PS5 loading within a sec or two, while the XB2 is taking a minute or two to load, as well as showing more pop-in?  I'd imagine in that case, some devs may not bother with the XBox.

Well, if the two rumors revolving around this turn out true, there is a SSD and a HDD.  I would imagine the HDD is for storing the majority of the games not being played, and would be upgradable by the consumer.  The SSD will be the same across all SKUs and will be used to store several of the most recently played games.  I believe one rumor said it was 1TB in size.

Until SSDs will finally allow a number of rewrites of the same order of magnitude of what mechanical HDDs offer, my favoured solution will always be a larger RAM, good ol' HDDs and possibly an additional SSD if OS and apps allow to use it mainly for data that are rarely written and rewritten, but very often read.
SSD could be a godsend for ivery often written data too, but this use would kill the drive quickly, it could speed up a lot swap for example, but for now this use must be avoided, better, and even faster, reducing need for swap by increasing RAM.
Anyhow, using SSD to store read-only level files aand app and system libraries can already be a fast and efficient application.

Next Gen is finally coming, can't wait for PS5 and Anaconda.

They did right at the very beginning ,but it was loaded so fast that you blinked and missed it.

If you think you are going to be flying around a map at the speed of light that this demo showcases... I have some bad news for you. - It's not good gameplay.

And PC tech is relevant. - Consoles are built from PC technology, they are PC's.
Towards the end of a generation many developers start targeting PC first... We saw it last generation with Frostbite, Unreal Engine 4, Cry Engine and more... To the point where the PC was looking next-gen.

The SSD is going to be an extremely valuable tool, but it's not going to be changing the way games are designed.

Provide me an example of how a game would be developed differently and thus take advantage of an SSD over a mechanical drive?

The basic principles of how a game engine will operate in regards to the host storage will remain the same. There is no "secret sauce". - There is no "Cell" or "Cloud" or "Blast Processing". It's just a faster storage drive... And we don't even know if we are allowed to use it to install games on, this could have been a best-case scenario with all the data dumped onto it... For all we know its just an SSD Cache drive and thus real world results may be substantially different.

In short... Let's not start hyping something we don't have all the details for.

And I have been using SSD's since they came out, I was an early adopted, I was running them in raid. - Many games I don't see a loading screen.

This certainly could be just marketing fluff in top of nothing more than a regular SSD being put into the machine, but I will wait and see before calling it just that. What has me really curious here is that even though they did cherry pick a game that already has really quick load times so that they could achieve a load time less than a second, they did so by a 9X increase in speed. Out of curiosity I looked through several video comparisons of games loading on SSD, and while there were a few bad ones that only got a 1.5X boost, the best range was around a 3.5x boost. To me this says one of 2 things. Either there is some special hardware solution, or (this is sort of answering your question), this game was modified to run differently so that it could load faster.

And for 20 years loading time have been high and in some cases dreadfull - looking at you GTA.

So a faster SSD instead of a slow HDD is a great improvement.

For Sony 1st parties they won't have any need to look at mechanical storage or PC from how what Cerny is pitching so far.

And even if your SSD allow for a faster load it doesn't allow for a faster traverse time.