I think I know what you mean but don't forget there is a specific and horrible case here too. Many people died and now the FBI has access to the phone. I don't know what the odds are that they will find anything useful in way of easing the pain of the victims or preventing an occurrence, but certainly it seems highly plausible. And at the very least a lot of resources going into this part of the investigation can now be used elsewhere. They were able to access the phone and (hopefully) it required some expensive physical+software breaks, which seems to be a reasonable compromise in the privacy vs security debate.

I think this is a great outcome.