You can't say you don't view something as negative because it simply doesn't matter to you! That's a huge letdown!
How is a huge let down? let's view the opposite. It is USB. You have to plug it into a USB port to charge it. Not so bad if you plug it into your console, when you set it down, except that you may set it down on a table near where you sit more than you ever get up to go to the console/TV itself (and in most cases I don't think anyone would want a cable coming from where the TV is to that table either), but that's no huge deal. You can still get up and walk to the TV to pick it up/put it down at least. Just a bit more exercise.
What is a huge deal is when you want to play with it plugged in (charging). Now what do you do? Play it close to the console? Have a very long cable coming from near the TV across the room? Play it close to a computer with usb ports? Buy a usb to AC adapter to play it near a AC socket?
In all these cases, there is an AC socket near buy for sure, as that AC socket is also powering that usb port.
With AC, you get to plug it in anywhere, with USB you get it plug it in only in really obscure places where there would be USB ports, which generally are not where you'd be playing games.