Possibly a bit niche, but it would be really handy to be able to take screenshots more easily – multiple key shortcuts are a pain to find in the dark when you’re not using the keyboard for anything else anyway.
I find that screenshots are a nice way to save something from an event and have something to post online for promo. Video capture is of course impossible live, so it’s very easy to work on something for a one off night and then find you have nothing to show from it.