We need altcoins as long as we interact economically over the net, with people we do not know (or simply with people outside our local communities). If we try to imagine what qualities a “solarpunk coin” should have, what are your thoughts? Do we know any existing coin, checking all boxes? This question is more about political economy of Solarpunk, then its technology.
I think you are implying a false dichotomy here, like money and trust are opposed. Anyway, trust in people doesn’t scale at all, it’s trust about platforms that can kinda scale. I do not trust a random person on the other side of the ocean i’ve never seen but if we use paypal and ebay i can kinda trust those 2 platforms