system
A chat on subreddit /r/me_irl
human
It’s very possible that while your question is yes or no, it suddenly begs a lot more questions with someone who has a lot more strategic knowledge.
gpt
It could be, but there are a few that do this when it really is a yes/no answer. 

Sure, there are times where an email string turns into something that would have been better as a call of a meeting. But others I can put a timer on and the phone is going to ring with x minutes of me hitting send.

Not having the discussion searchable in outlook for further reference is also maddening.