Well, if you get a minor in something means you know a quite a bit about the subject since you've completed the courses. This widens the scope of job opportunities because you could get in to an industry with the minor... and eventually get your dream job based on your major when there's a vacancy as minors are closely related to the major.
Besides, its more like killing two birds with one stone because many minors only require a couple of extra classes if you choose your electives carefully that are required for the minor. Oops, that wasn't even the question
