Oddbean new post about login | logout Encrypted spam only affects the receiver, who can easily mark as spam just like any other DM.
it also clutters the server (relay). disk space is a scarce resource as much as attention is.
You can have a deal with your users to delete GiftWraps after some time to declutter. But that is between the replay operator and the user. The same clutter can happen with DMs. So this is not an issue of the new method.
Nostr right now is a small close-knit community like early 90's Usenet. We need to be prepared for an eternal September.
Relay monoliths that we have today will never scale to where we are going. None of today's architecture will survive.