I agree that BTC has little inherent value, it hasn't turned out all that useful. Even if you believe the advantages of crypto are worth all the disadvantages there are blockchains that are much better.

But similar things can be said about many things, and some commodities are able to sustain their bubbles for decades or centuries. Gold is going strong for millennia, with a price far exceeding its practical value. BTC probably won't last that long, but unless it's disrupted by legislation it might still have decades left in it.