Ya I saw that earlier. I think it would be great to develop a system that provides the practical benefits of an ID-less system on a platform like nostr that is fundamentally based on public identities (pubkeys). You get the best of both worlds!
We can use temporary npubs that are not linked to long-term identities and rotate them all the time. Iris.to messages already do that. The code is here: https://github.com/mmalmi/nostr-double-ratchet
Discussion
Temporary npubs are quite similar to message queues. Maybe you could also send a "delete" event to relays after receiving a message.