I am going to take the contrarian view. Beno for his faults has talents that some other NBA basketball players don't have - he is a pure passer and has a fine motion on his shots, and when, he was the 2nd point guard in the past put up pretty good numbers.
There was a comment on air during the playoffs that Beno would start for many teams, and although, that is highly argueable, he would I believe in the right system (and with renewed confidence) he could be a valuable player.
What the Spurs should have done was trade him. I believe that is still the plan rather than waiving him.