This is conflating two different communication modes.

Chat is quick-turnaround; you send me a message, I respond to it then and there.

Email is long-turnaround; you send me an email, I check my inbox at some point, draft and think over the response, and then send it. This may take several hours or a few days.

Trying to turn email into an instant-communication mode will just remove the sanity of having more time to respond.

I somewhat like the idea, but couldn't you make it no-login? Just send and email and go?

And I think it could leverage email somehow. Maybe save and send the conversation on an email to all the parties involved after some time.

Or it could just work for some people using just email, for others using the chat room, seamlessly.