The internet was something new, and it fueled a speculation bubble. I think we are seeing something similar with cryptocurrencies. Are they something innovative and potentially useful? Yes. Do their valuations make sense? No.
There is no question that there was a bubble, but the value of the internet as a platform for building businesses now far exceeds what people expected it to accomplish in the dotcom bubble.
I'm not saying cryptocurrencies will have the same fate, but it's not impossible.
I think their valuations will make sense, but no, not right now. I think this whole pile is breaking ground on new tech, tech that will redefine some of the things in our lives. Will Bitcoin / ETH be what holds on? No idea.