I think not being able to receive it is worse than not being able to send it. Either way, one of the things that sets Nostr apart from centralized social media platforms is the ability to engage with notes privately or anonymously. That’s only possible with Zaps.
You sent me a zap, which is public not private, it is anonymous, it does contain a message, but the message is not private. I don’t think it proves your point. Don’t get me wrong. Zaps are added value, but Nostr would still have many advantages in term of data résilience, décentralisation, portability… even without zaps.
You can communicate anonymously and privately on nostr without zaps. Give to Nostr what belongs to Nostr, and to the zap (one NIP) what belongs to the zap