What specifically would make you earn sats? As in: who's paying?

Good question ! That could be a simple BTC association wanting to promote the BTC. A bit like Fountain or Blink giving few sats to incentive you to learn BTC. But yes, for a car GPS it's different. Or simply seeing ads and being paid in Sats in exchange. I would prefer see ads and be paid in Sats (Brave model) than just seeing ads to let us use an app free.