Oh, this e-reader has lots of productivity features. You can highlight words (which are later stored in a separate folder), make bookmarks, easily translate words, use screen reader, etc.
I use it mostly for work and academic papers, not for amusement.
Most of the regular simple pdf viewers on the PC don't have this kind of productivity functionality in mind. They might have some, but in general they are not designed to work with read-only text.