Well, A library is a great place to go to, whenever you have to learn. It's quiet (At least it's supposed to be quiet haha), you have a lot of space (big tables etc.) and it has a great atmosphere. Furthermore nobody bothers you, as well as nothing really distracts you from learnon. Also you have people there that will help you, if you need some help. If not, you have a wide coice of books (Depending on how big/well-resourced the library is)
See? There are a lot of Advantages. But when I think of the disadvantages of using a library there is only one thing that comes to my mind, which is the fact that the library is open only a set number of hours.