The issue seems to have not been as irrelevant as all that. Hillary's campaign was definitely taking it seriously and Hillary herself even admitted that their reaction was overzealous. In Saturday's debate Bernie publicly apologized to Hillary for his staff member looking at the data which should never have been available in the first place, and then went on to say how he wants a joint investigation by their two campaigns into the NGP VAN screwup that shouldn't have happened in the first place. Bernie also mentioned being upset that the DNC decided to penalize his campaign without even consulting him regarding an incident that they caused. He said being banned temporarily from the software was "crippling" to his campaign, for which I'll take him at his word. He also mentioned that there was no evidence that his campaign's data wasn't made similarly available to Hillary's camp, even though no one there came forward to say so. Recall that it was the honesty of the Sanders campaign that got him punished in the first place. Hillary, while happy to accept his apology, nonetheless seemed entirely unenthused while Bernie was mentioning a joint investigation into what went wrong. You'd think she'd have at least feigned interest in showing him good faith in the matter.
I don't think this issue is the end of the world, but I found the connection between the founder of NGP VAN and Hillary's campaign troubling. I'll be disturbed if this incident is mentioned again by Hillary in further campaigning as a strike against Sanders.