It has a growing collection in paper because that's the main medium for the production of scholarship and information right now and for a long time to come. The digital information we bring in, or that we create by reformatting some of this paper material, is all part of the same collection. It will be integrated, and scholars will use whichever information they want in whatever format they find best. We hope to create the capacity to deal with this explosion in digital information. We've got hundreds of years of understanding about how to do this with books.
Digital information creates all the same problems.
You have to acquire it, select what you want, and let people know where it is and how to retrieve it. You need to know who can access it and you need to protect it from being misused. Some people think this is very easy. It turns out that the digital world is very complicated. There are huge amounts of material in digital form, but a high proportion of it is junk.