Honestly while this is a pain, I'm all for it. There needs to be a way for user's to guard their entire chat history in the event an nsec leaks. If a bad actor is just hoovering up my DMs waiting for my nsec to leak, then they may be able to find something from years ago that in any other application would have been able to be deleted. If people shared home addresses or any harmful personal information over a DM it can be vulnerable in time. Private relays help/fix this issue, but not all user's are going to be able to configure one. 

Until the day comes where messages can be ensured bad actors aren't hoovering them, I will not suggest any user share any personal info over a nostr DM with me! Even with nip44, it's still known what language the user's is likely to be speaking in, and therefor the alphabet, and even intent, which lowers the probability of a brute force ciphertext attack. While that still may be a high number, I don't want to bet on it if it's possible to rid that probability entirely!