I hate read receipts because the UI interactions which tend to make an application respond with a read receipt if it is configured to do so don't actually correspond to me having read the message; that is, they fairly consistently prove to be false positives in their advertised role.

(And, if instead they are being confirmation of delivery-to-inbox, they aren't right for that role, either, since they rely on interaction that happens long after that. I can receive, see the sender of, and delete your message without sending a read receipt.)

There is basically no useful information for which they are a good proxy.