Luis "Lou"’s Answer
Yes, it matters.
It isn't the only thing that matters, but it matters.
Think of it from the point of view of and employers: you have two equally qualified candidates. One has a 2.8 GPA, the other has a 3.4. Which would you rather hire?
GPA is not a measure of smarts. GPA "tells" you how hard someone work in school, thus giving you a supposed idea of how hard they will work for you.