I follow this artist on Twitter and NFT is what let them quit their day job and make these animations full-time. I don't like NFT (and I don't have any) but I think this might be one of the few positive effects of people buying NFTs.
So selling NFT is indeed a separate source of revenue from donations.
it's the same magic value assigned to art pieces themselves.
It doesn't matter whether those buyers of NFTs make a profit or not - i don't care. I personally don't believe NFTs have value, but i can understand how other people could believe they do.