1. Some books have horrible formats. In the physical books, shitty formatted texts are not printed (hopefully) and fixed. 2. Too many filetypes and some books tend to be only in a particular format, hence creating a separation. Though this is easily remedied by using converters, it loses formatting sometimes.

I still prefer EBook reader for the convenience. However, a physical book is great. I find it better but I do not have a good reason as to why.