Your advisor is helpful for a lot of different things. The main reason everyone sees their advisor is for class selection. Our advisors are required to approve us before we register, so we all make appointments to meet with them before registration to talk about classes. They make sure we're not forgetting requirements or taking classes that won't help us later on.
You can also go to your advisor about choosing or changing a major, going abroad, graduate school, or any other academic related situation.
Of course, advisors are for more than just academics, and most students take at least one class with their advisor during their four years. They are available to talk about any issues you're having, internships, recommendations, and whatever else.