If you haven’t tried it, Touch My Katamari uses the back touch screen and it’s quite fun. I agree it’s really not needed but occasionally someone does something fun with it.

Fellow vita lover here. The homebrew scene is top notch and still amazingly active. I haven’t gotten around to setting up retroarch (it’s on my to do list!) but I’ve played some nes/snes on standalone emulators and they mostly work well, though I have noticed some audio artifacts on some games. OCing the CPU and enabling frame skipping seems to help with those, though. But overall, I’m still thrilled with the device.