I’m assuming it’s to make sure there’s not long waits to try them. Giving a set number of tokens to visitors means they can roughly control the amount of time someone spends with those games. One person can’t just buy 100 coins and spend all day on the same game.
Could have just done a ticketing system reserved in advance with fixed time blocks, though. But then your museum tour is on a schedule.
To put it a different way, centaurs have 6 limbs. I think it’s not so much about making creatures out of the “missing” parts as much as it is swapping which part is the horse and which part is the human, so these also still have 6 limbs.