Well it would have been an issue if Bush 1 had actually run a campaign and Matelin was worth a crap. It's a nice juicy lie to drag around to counter his other promises.
Beating her would definitely be the best, but getting her to make a promise we can use against her is a good just in case.
You have to remember that for all his faults, Clinton was a clever snake-oil salesman who could have convinced 30% of the American public that he was a Hall of Fame baseball player. Nothing ever stuck to him because his campaigns were largely staged events that were 70% bullsh!t and 30% exaggeration.
Hillary, though, is a different story. She is far more ideological than Bill ever was, but also far less charismatic. The only way she will ever win is by either convincing people that they should be moved by dire circumstances to overlook her lack of charisma (highly unlikely), or by getting a legitimate third-party candidate involved in the race (more likely).