You seem to be proposing that not passing a law against proof of work cryptocurrencies somehow makes it more likely that we will quickly pass a law generally "solving the climate issues" ... I think that is highly unlikely, and in fact I think the opposite direction is more likely, that passing a law banning PoW cryptocurrencies makes us more likely to pass another law which solves climate issues in other ways.
Banning PoW cryptocurrencies is not a big enough priority for anyone that it will be a motivating factor to move past the other issues surrounding the climate debate, especially not anyone on the side of "don't do [thing] to fix the problem". I don't see any other mechanism by which it makes passing other climate legislation harder.
Banning PoW cryptocurrencies removes money that is currently on the side of "don't pass climate legislation because it will harm my PoW cryptocurrency business" from the table. That makes passing future legislation easier.
In general, trying to solve all the worlds problems at once doesn't work. It's too complex, you paralyze the decision making body with too many tradeoffs. When something is obviously bad, banning it immediately not only has the effect of meaning it's gone immediately (and doesn't hang around until you solve the whole problem), but it simplifies the remaining problem for the decision making body. This makes them more likely to come to a consensus on exactly what to do in a finite amount of time.