Kirk, when I say (I don't want to speak for everyone, but I assume the sentiment is not limited to myself) that "managers don't matter much", I'm talking about on field decisions. Line-up constructions, plays called from the dugout, pitching changes etc...
Personal decisions are outside the scope by which I judge the value of a manager, though this was an excellent decision.
FWIW, I think Gibby has done (for the most part) a great job with the few things a manager influences during the game (not much bunting, generally good use of the bullpen, though he is still too much of a "slave to the save" with Janssen).