In a post-scarcity solarpunk future, I could imagine some reasonable uses, but that’s not the world we’re living in yet.
AI art has already poisoned the creative environment. I commissioned an artist for my latest solarpunk novel, and they used AI without telling me. I had to scrap that illustration. Then the next person I tried to hire claimed they could do the work without AI but in fact they could not.
All that is to say, fuck generative AI and fuck capitalism!
You said this very well. It's no more stealing than you looking at a piece of art and remembering details, and producing output from that input no more immoral.
It's clearly necessary to have the broadest possible training data in order to be useful at all. If it isn't familiar with Spider-Man it can't create art depicting an accurate representation of him.
If anything I'm proud of the pioneers ignoring the legal implications and pushing forward, instead of letting copyright limit what AI understands.
Every single picture on the Internet, ever created, unless specifically licensed Creative Commons or equivalent via licensing has an implicit copyright. AI art is impossible under international copyright framework at written, so thank God they ignored the insanity of intellectual property fuckery the US has imposed on the world.