Mainly for altruistic reasons I’m guessing

Some do, to support the development team. It’s completely optional. NOSTR is built on people that give their time and money voluntarily. We will have more and more payed services here since showing ads and selling user data is not an option.

Theres a few small startups on nostr right now : primal, yakihonne, damus, nest, etc… I try to help a little of each . We know it’s a good way to develop the protocol.