I saw the Dallas-Sac game last week when Beno was doing well up until the second quarter when once again he gets the ball stolen in the backcourt, the loose ball is passed to Dirk, and DN drains a long three, capping a Maverick quarter ending run that extended into the second half. Dallas went on to win the game with the momentum from that run. In other words, Beno has better stats with a bad team due to his extended playing time, but in the end, he is still not reliable when it is crunch time.
As for the Spurs trading Beno at his lowest value, it is hard to build up his value when he kept getting hurt here and letting his personal situation get him down in the mouth and at the end of the bench. The Spurs are not in the business right now of giving bench players heavy minutes to build up their confidence/value while at the same time winning 65 to 70% of their games. That is just not realistic.