Go read the thing! Liner notes provide more than fodder for fact geeks. More importantly, they provide info on who made/provided what on a given record, and can point those interested in the direction of these other musicians' work, should they be so inclined. Which we often are. Of course, a lot of information on recordings is available online nowadays, on Wikipedia, discography pages and so on, but when you buy a physical record, most of this info comes with the package. Downloading files, in order to get this information, you'll have to do exstra work.