Good question. The idea is to create a small challenge/hurdle/gate for participating. If you can pay a sat (atm ~1/3000 of a dollar) it more or less proves you're a real bitcoiner. You're less likely to post FUD or trader bro price stuff.
If you post good content or comments, you'll likely net gain sats.
In the end it's a bit of a social/economic experiment. If people prefer to not have the 1 sat hurdle, I can remove it. I just suspect the mean would revert to reddit/twitter shitposting.