I don't think this is practically much different then answering one thing. If you give one answer and 3 "I'll get back to you on that"'s-- this creates a promise of a future asynchronous answer, which is only as good as your word. People often have too many tasks, so to get those remaining items on your queue, they'll have to ask you again.

As the recipient, it's more challenging to receive the future promise of an answer with no SLA.