Pretty sure there's no real aiming as your punches are always thrown right at the opponent. What you're able to manipulate is their trajectory.

This is what I mean: you can manipulate better the trajectory with montion controls. 

Motion. This is a game designed around controlled movements in terms of curving punches and aiming them. In that context, Motion controls allow for much more natural control scheme since the gestures give you a better idea of what you're actually doing. Plus, there's a certain satisfaction to punching and feeling it hit you're opponent that a conventional control scheme couldn't replicate the same way. Motion Controls are an excellent tool in that regard when done right.

I think one of the most tragic things about the Wii was that it never received a proper successor to build on and refine the concepts and ideas it introduced. With the Switch, that opportunity may finally arise, and hopefully ARMS can shut down the misconception of Motion Control games always being detached waggle fests that are imprecise.

I need the workout, so yes

In case anyone hasn't seen it yet, here's the traditional controls:

I have 3 concerns. 1: Why is punching not the shoulder/trigger buttons? Woulda made more sense. 2: Guard and Grab should be their own buttons. 3: How do you curve punches? Are you just not able to!?

This set-up would only make sense if the trigger buttons are how you curve your punch, but it doesn't say if that's the case.

I would definitely be concerned about curving punches from that layout, which in fact was my first thought when they confirmed you can use traditional controls. If there isn't a trick to it(like the trigger buttons as you said) then this would seem like a major disadvantage.

https://nintendotreehouse.tumblr.com/post/161100556247/welcome-to-arms-part-1-motion-controls

After reading this, I understand why motion controls are the superior option compared to traditional.  Two big takeaways I got were --

- Curving punches are analog.  The more you curve your wrists, the more the punch itself curves.  That seems like it's going to be too awkward to use with traditional controls even if they used an analog stick to trigger curved punches.

- You can widen, shorten and direct the grab area for throws by twisting your wrists like with curving punches.  Again, seems like something that would be noticably more inconvienent using traditional controls

It looks pretty fun with motion controls so may as well give it a try.