There is definitely a difference in looking at rare books online vs. seeing and handling them in person. In viewing copies, there is a lot of the work that is overlooked. Looking at old texts online is a very informative thing to do. However, it should not be substituted in place of looking at such things in person. Although our society is very tech dependent, much is missed in the fast paced world. For example, just from class on Tuesday had we been shown the books online rather than in person we never would have noticed the parchment covers, the hand printed cover pages, the smaller vs larger paged books, or the immensity of the 13-pound book. Although those details may seem small, they are still part of the history that we would have missed by viewing such online.
Going along with the difference between viewing things in person versus looking at copies, what comes to my mind is pictures. Over the summer my family always goes to the beach. Of course I bring along my camera and end up taking a thousand pictures, to which I compile into a slideshow. This year my brother was unable to attend the family vacation due to work, so I showed him the slideshow. (Keep in mind, we always go to the same place, stay in the same house, and do relatively the same type of things when there). To my surprise, although he is extremely familiar with all the places we went, he had so many questions! It was mind blowing how much is lost just viewing the experience through pictures, rather than actually experiencing it first hand.
An example of this is as simple as typing in the words sunset pictures on google, to which a whole stream of pictures appears in front of you. However what are you missing by having not been there when the pictures were taken. All you can do is look at their beauty, but you can not connect with them unless you were actually there.
The end of your first paragraph brings into play perspective. We simply won’t “get” how big a book is or how much it ways by looking at an image on the screen. Though we can memorize facts and plenty of information, a really deep understanding won’t occur until you can engage with the material face-to-face… face-to-cover.