Yes, the current price of crypto is based on speculation, not in their current utility.
But there also was a dotcom bubble 20 years ago. Does that mean that the World Wide Web is useless?
Cryptocurrencies will be highly useful as stores of value and maybe as currency. We're just not there yet.
This is just the Gartner hype cycle, with the addition that for the first time we have a global market completely parallel to the traditional one with much less regulation. No wonder people are going to speculate with it. It's our new toy.