Crypto currencies have all seemed like an obscurantist version of hot potato. Either the hash gets too long to calculate effectively or the amount of money at stake means very very smart people will start finding ways to hack the coin (and they will).
But basically the deal crypto developers are trying to make with me is to trade US backed dollars for "fun bux". These developers are usually very smart people - often much smarter than I. But I don't like smart. Take US dollars. Little pieces of green paper are very uncomplicated and if anyone starts copying them armed thugs show up at their house to have a very serious discussion. And my corner chemist takes dead presidents on delivery no questions asked.