I bought iPad mini 4 by upgrading from iPad mini 2. Main reason is to increase storage size, my iPad mini 2 was 16GB. So I needed to replace contents like movie and book.
Almost my books were scanned because I didn’t want to keep space and shelf for books. And I want to read anytime when I have a time.
Anyway, latest iPad mini is thinner and lighter than old one. It’s easy to read.