eBooks from Amazon are locked down and distributed in a way that is hostile to both authors and readers. You don't own the book. You cannot lend the book. Renting Kindle-compatible eBooks from the library is arduous and limited by artificial constraints; you literally need to return a book before another person can rent it.

When I want to search an Amazon eBook that I "own", I have to log onto Amazon's cloud computer. Further, the open .epub eBook format is not compatible with the Kindle; readers must use Amazon's .mobi file format. Some .mobi files are incompatible with my device, but I have only discovered which ones after I purchase. I cannot even highlight my purchased Amazon eBooks without running into usage violations. Highlight lengths have arbitrary limitations.