Actually, I fully understand this and I agree that it should be there.
It's so models don't miss what the user is asking/wanting/saying. Imagine you're in Doggystyle, for an obvious example, the user is messaging you and asking you to turn back around so he can see your face... you don't hear it, this leads to them quitting and giving you a bad rating.
So, in my opinion, I truly do understand and think this should be there, ALTHOUGH I do agree that it can be annoying, but only if the user is sending lots of messages.