1. Too hard.
2. The feature is still being developed to making it an event type now is premature and will only lead to half baked NIP (like what we saw with NIP04)
3. Even if we put all that effort in, there is little guarantee that anyone else is going to go and build an app that uses that spec.
So all in all, a HUGE effort for very little reward.
Protocols move at a different pace that products.
My priority is building a great product that survives in the market.
We can always come back later and make it Nostr compatible if we survive.
To do it the other way around will all but guarantee our failure because we burnt all our resources for Nostr, and not the users.