I don't see why anything needs to be "incentivized". How do you know that zapping more than whats happening naturally is good?
It is as though Nostr would earn tax from zapping and wants to incentivize zapping with shiny badges. It'll be pointless if someone ever does it. Anyway.
Here's a true incentive for zapping:
If you tell me 5 creative ways of using zapping for your benefits, I'll zap you 69 sats for each.