[...] Buying something in expectation that the price will rise without any intrinsic value is the definition of bubble. [...]
Something can have an intrinsic value and still be part of a bubble. Housing, for example. Or even dot com companies.
It's only when the prices that people are willing to pay far exceed the fundamental value of an asset, that bubbles are born.
I agree with your sentiment though. Cryptocurrencies as a technology are an unprecedented value proposition that in the long run will not be lessened by price fluctuations.