// You may receive the Ack, but it gives no information about how your message was received by the recipient.
Yup. And also, what you're getting an ack to matters.
Not helpful:
you say: Project X is now priority 1.
I say: I think you said, project X is now top priority, right?
you say: ack!
Helpful:
you say: Project X is now priority 1.
I say: Just to confirm - we are going to pause project Y and Z, and move Alice and Bob to X. That probably means We are going to lose Acme as a client because they are waiting for Z. I can see how this might make sense, but just wanted to double check.
you say: I didn't think about Acme. No, I didn't mean that - let's rethink.
One ack gives you no new information, one enables a really good communication. If you said "Ack" in the 2nd case, that's mean a lot!