YMMV but I don't see any difference at all.
If anything the form factor of the e-reader makes reading more comfortable. I'm not having to hold the book in a certain way to hold the pages open. It's always lighter, which is a big advantage for reading large books. It's also a bit smoother/faster because page turns are instantaneous and using the holding hand. And I can read under light rain without worrying about the book disintegrating.
The e-ink display is akin to paper for my eyes, and more comfortable to read at night with it's reddish backlight as opposed to a physical book with a nearby lamp.
On a side note, I do quite like the built-in dictionary/Wikipedia extract feature in Kindles. For some books (eg. Russian classics) it's quite useful. There's also a feature which based on a slider annotates individual words (slider dictates the complexity of words to annotate from some to many) in-line in the book, which I can see as being of enormous benefit to a new or young reader.
I do still enjoy going to physical book stores and browsing the covers, blurbs and first chapters. On the other hand, when I'm reading about a book online it's nice to be able to buy it and instantly start reading.
Paper books have a bit better typesetting and for reference books/textbooks they still have the edge but for linear fiction/non-fiction? Give me the ebook every time.
I replaced physical textbooks with an iPad with the Kindle app on it, since whether it's an iPad or textbook it's something that stays at home. It works really well, especially side by side with Goodnotes for studying.
A better idea is a book trading platform where you offer your books for points and then use the points to trade for new books.
I think the words are actually sharper but most of all the lighting is always absolutely perfect. The size is perfect.
Even beyond that though, my absolute favorite is an audio book read by Robertson Dean. Hopefully someday soon we can have AI Robertson Dean read any book.
My ideal situation would just to lend my 300 books to a library that ships anywhere in the world when I finally want to read, and then take it back when I'm done. Or a PDF...
But now they are all here, and I rather have the space instead of the books...