There's definitely value in cryptocurrencies, in the sense of significant promise of being useful for new types of financial instruments and transactions. This does not preclude the possibility of there being a crypto bubble, i.e. demand/excitement causing the price of the currency to rise far far above its current level of usefulness.
The ultimate usefulness of cryptocurrencies is determined by things that may take years or decades to figure out a way to do: everything from 'is it a good store of value' to 'can I shop with it on Amazon?' to 'can I use it to issue equity for my startup?' This gradual growth in usefulness does not really match the tendency of coins to double in price in very short periods of time, so the question is whether the temporary bubbles and disappointments are severe enough to disrupt the gradual growth in base value. This is no different from real estate bubbles potentially making things painful for people who just want to buy a house to live in it.
Ya, definitely agreed. Although I would add the caveat that the rapid growth in value of these coins is not necessarily that crazy. The market cap of the entire ecosystem is still less than 100 billion. Which, no question, is a lot but it's still less than 1/7th of Apple, which is only a single company. So while I agree we might be in a bubble, I don't think the current crypto valuations are at least prima facie necessarily a bubble.
The ultimate usefulness of cryptocurrencies is determined by things that may take years or decades to figure out a way to do: everything from 'is it a good store of value' to 'can I shop with it on Amazon?' to 'can I use it to issue equity for my startup?' This gradual growth in usefulness does not really match the tendency of coins to double in price in very short periods of time, so the question is whether the temporary bubbles and disappointments are severe enough to disrupt the gradual growth in base value. This is no different from real estate bubbles potentially making things painful for people who just want to buy a house to live in it.