In either case it's a license. The difference is what the license is bound to.
Amazon kindle ebooks are bound to my Amazon account (I can read same book on my Android or Amazon Kindle device as long as I sign in with same account).
With a physical book, the material is literally bound to the pages of the book.
In neither case do I own the copyright. It's the same as owning a film on DVD or VHS.
You cannot make copies of the content of the book to sell it, you cannot take large excerpts of the book and sell those either. In short, you do not have full intellectual property rights to the book.
You have licensed a single copy for the purpose of reading the book.