Maybe Bitcoin isn't a speculation bubble; maybe it's something new. But if you ignore the underlying tech and just look at the price chart it sure looks like an old fashioned speculation bubble, and those traditionally don't end well for the median investor.
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.
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.