My assumption and understanding is that Zaps are geared to target posts specifically, and non-zaps are just an easy avenue to get to tipping someone’s lightning wallet for whatever reason. That’s my view that could be wrong.

Also, I think an anonymous zap could be used just out of generosity where the zapper just wants to give sats, maybe a larger amount, but not receive any thanks or something. Not entirely sure though. The option is nice imo.