You can do that on the Vita as well. I've spent very little time with it turned on. Like, 3 or 4 minutes with Freedom Wars. I have some friends who actually use it a bit.

But how do the games look? Why would anyone want to use it other than just to see how it'd look?

I'm not a fan of how the games look versus the normal color scheme, so, not that good to answer your first question. As for why anybody would want to use the feature? IDK. Weirdos? :) Some people with visual problems apparently have a practical use for it, as it can help them see. Other than that, it's a matter of taste I suppose. I'm tempted to try to log in to VGC with the Vita and upload some screenshots for comparison, but the Vita browser on this site would probably be hilariously bad.

OK, then! I guess it could help people with visual problems, I hadn't considered that before.

omg the new headphone volume is amazing, I actually found myself turning down the volume while playing MK8 rather than maxing it out and wishing for more as always, can't wait for my next flight with the system now, should be able to hear it perfectly :)