[nerdponx]

Look up "artisan keycaps". Not only do people use them, they collect them, and certain specific rare and desirable artisan keycaps can be worth a lot of money. The high quality ones tend to be cast out of resin in small batches (sometimes literally just 1 in a given color/sculpt combination) and sold in short-duration raffles. People tend to put them on less-used keys.