Sorry, could you please explain how exactly they are useless and worthless? Do you mean it in the same way, like BTC, USD, EUR etc. pp. are useless? There is gold, so why would anybody even need silver? There are diamonds, but why do people buy sapphires, emeralds or even - the "worthless" in comparison - pearls?
Maybe this helps to understand. Why would people buy old cars and spend a fortune on them? Why do they buy even old baseball-cards for amounts of money, nobody else is possible to understand?

Baseline: Maybe the clue is, to ask what something is worth for you personally? The ones will say: bitcoin, the others: Mooncoin.