Beeing in a bubble that eventually will burst and leave a lot of scars to those who overvalued it does not mean that the whole thing is bad ore useless.
That's. What I said, most likely a big share of cryptos will die out when the bubble bursts, but a few will survive and after the dust clears we can expect them to rise out of the ashes. But it might be only a small part of the market and many who put their money in the wrong chaine might loose a lot.