I really like it for two things first It could be another radicalization vector for people inside not that radical movement's like some parts of the climate movement. And second it gives me and my comrades a vision and a world to fight for. There is a reason that optimism stands in the two first lines inside the Solarpunk manifesto.

We are solarpunks because optimism has been taken away from us and we are trying to take it back.

We are solarpunks because the only other options are denial or despair.

Also you are completely right with it being Anarchist:

At its core, Solarpunk is a vision of a future that embodies the best of what humanity can achieve: a post-scarcity, post-hierarchy, post-capitalistic world where humanity sees itself as part of nature and clean energy replaces fossil fuels.