people always propose this like an obvious and easy thing, but when you get into the weeds its not. How does querying work? Delegation was something like this, but nostr devs deprecated it because they claimed the query complexity was too high. you had to not only look up a single key, but look up N keys for every possible child key that was used for a users profile.
I personally thought delegation solved it elegantly, as it’s the only way i can think of querying actually working in a multi-key setup, and it doesn’t require clients to change anything to make it work.