One real world scenario I encountered while testing coracle is that if only nip-44 is implemented this is not backwards compatible with nip-04. Not sure at all about NIPs best practices, and if this is best addressed at all in NIPs, SDKs. 

I think nostr:npub1jlrs53pkdfjnts29kveljul2sm0actt6n8dxrrzqcersttvcuv3qdjynqn had thought this through on coracle, and there was some bug he squashed to make these DMs NIPs compatible.