Use as currency was always the weakest aspect of block chains. The real growth is in smart contracts, where I am absolutely certain will be used in the next 15-20 years.
Agreed, and Ethereum (not the Ether crypto, but Ethereum itself), is the leader in that at the moment. I believe smart contracts will be prevalent within just 3-5 years, not 15-20. Ethereum has dropped along with the others, and my son, who is very crypto savvy says buy.