Couple of levels.
Snap to button mechanics are too easy first off. That usually is the only reason I need lol. For others whom that isn't enough though, you need to look at what the mechanic is actually supposed to do. Making reads and giving a representation of where the QB is looking.
I hate the sky cam setup all together, but that's a topic for another day. This is what we have now though, so having a snap to button doesn't really change anything from how it currently is. I know this because I started out using the trigger method for QBV. What I did was lock the cone on an arbitrary receiver, but one who, based on my read at the LOS, probably wouldn't be the right one to go to. So I basically picked the receiver that I thought had the least chance of getting open, based on pre-snap read. Fine. So I snap the ball and precede to hold the trigger button for the snap to and leave the cone on him the entire time all the while looking at the other receivers I deemed to have favorable matchups. And the one who the cone is on too, cause this is skycam after all. Once one of the receivers I thought would be open, comes open, I press the receivers icon to look at him then press the same button again to throw. This happens in quick succession. It takes barely more time than to just press the button once.
So what happened on this play? I casually left the cone on someone I never had any intention of throwing to. Why? Because I knew that I could see the entire field anyway and it would take less than a second to throw to the player that was actually open.
What did the defense get out of it? Nothing. Nothing? Yep, nothing. They got to see my cone sit there the entire time on a decoy and had a millisecond to see the real one light up before the ball was in the air. So what is the point of the cone then???
With the Right stick, the cone moves pretty fast still, but slower than snapping. In that same scenario i would still look at the decoy, but I might have to look at one closer to my real target. I might move the cone side to side thinking someone is about to be open then change my mind because the receiver wasn't or no longer is by the time I got to him. With the snap to i can look at a receiver on the left sideline and throw to one on the right in the blink of an eye. With the RS I'd have to sweep it over there giving the D a little more warning. With the trigger I always look exactly at the receiver whose button I press. With the RS, I might over or undershoot him because I'm pressured.
Basically the trigger method defeats the purpose of the QBV. It just requires that I hold a trigger down and rapid press the same button twice. The RS is analog, which is how a persons head really turns, doesn't always snap exactly to the receiver, approximating a QB having to actually locate the receiver, because even though he knows the play and where the receiver should be, he isn't a robot and can be off by a little on any given play, especially when hurried. Finally you are more apt to actually MOVE the QB's vision with the RS, just because you can't rely on perfectly getting it on the receiver every time via button press. In other words, there is a much better chance that you make reads through the interface and not just with your own eyes, giving the defense something to key on other than the wrong receiver every single play.
Now, even the RS is flawed, because again, you can still see the whole field and don't have to actually go through progressions, but if we are comparing the two methods, the RS is by FAR the lesser of two evils.
So yeah, that's why I say it's the right way. Even though both are really wrong.