This is an open ended question in a sense that if you look at cryptocurrencies just from bitcoin which can be earmarked as the Adam Smith of cryptos, then it was made to be a currency.

But then where does other cyptos such as those that build on top of other cryptos like ethereum?

So it’s suffiice to say that cryptos have evolved to not just be a medium of exchange (which it was meant to be), rather it is a digital representation of assets in the virtual world.