Jamie seeks out someone who won't talk and tell everyone how bad he is with his left, so he picks Payne, who can't talk (no tongue).

I thought for a second that was the direction that they were going on the show, because Jamie says, "I need someone who won't talk," but of course they pick Bronn. It makes sense, as the actor who plays Payne was diagnosed with terminal pancreatic cancer last year, and has elected not spend the rest of the time with his family and doing "farewell" musical performances (he was in a few bands during the '80s).