On nostr people usually just do it for fun. Some people have paid me sats for running a relay that is open (and free) for anyone to use. One user wanted to pay for a domain I bought, so they just sent me sats for it. And a looot of people sent me some sats as a birthday gift a week ago (they were way to kind, sent way to many sats).

On a more serious note, some bitcoiners really like the idea of “value for value” (V4V) where people pay eachother for different kinds of services.

One example is stacker.news which basically is a reddit clone but upvotes are replaced with sats. So you can tip sats to both posts and comments you either find valueable or agree with or whatever other cause. If someone writes a good guide you find helpful, you can tip them some sats for their work.

Another example is Fountain.fm which is a podcasting app where you stream satoshis to the podcast you listen to and the satoshis goes directly to the podcast host (or whatever they have set up). On some podcasts, you can actually get paid x amount of sats per second or minute to listen. You “stream” sats back an forth as the bitcoiners call it.