But renewable is all wasted if there is no demand. Hydro power used for bitcoin mining doesn't find a new user immediately if bitcoin stops and the power can't be stored long term so it can be wasted.

Hydro is the one type of renewable with built-in long-term storage.

I think you misunderstand. Once the power is generated it can't be stored for long. And I understand your point but you can't hold water in a reservoir/dam indefinitely, at some point you either use it to generate power or you let it flow through without generating power because otherwise the dam overflows.