I don't really understand why they wouldn't just use a supercapacitor instead of going to great lengths to work with a "small" capacitor? For the size/weight of

I don't really understand why they wouldn't just use a supercapacitor instead of going to great lengths to work with a "small" capacitor? For the size/weight of the old batteries you could probably put 30-40 farad worth in, which I would think would be plenty. The energy harvesting buttons have to be incredibly annoying ergonomically - for gaming, you do NOT want buttons that are really hard to press.