Collecting antique and older books can be done in many ways. One can collect the classics or, if you are an ornithologist, bird books. You can collect by bindings of leather or early paperback dime novels. There is a niche for just about everyone. Quite a few people collect Victorian era books because of the fantastic artwork and the beautiful design of the covers. 
This was a particularly good period for publishers to create high art books in large quantities. The industrial age brought forth new technologies in printing that enabled larger print runs of higher quality books. The same technology also enabled them to drop their prices. No longer were books a luxury that only the wealthy could afford. The completion of the American railroads also gave the publishers a much larger market in which to sell their books. In many ways, this created a mini Renaissance where knowledge was spread at fantastic rate.