The main point of an ereader for me is that if I didn't have one then many of the books in my genre just wouldn't be available to me. Some of them I might be able to get with print on demand, or by importing, but at an inflated price for a paperback compared to a paperback I could buy in a shop.
This gives small presses a long reach. People all over the world can access books from a small press which couldn't possibly afford to distribute paper books internationally.
They keep books available that would otherwise have disappeared and only been possible to find second hand.
They're good for writers in that they give them longer to build up a readership, freeing them from the need to make it in six months or whatever before the book stores stop stocking the books.
My paper book collection had reached a "one in, one out" stage. There's no more room for more bookshelves, never mind room ON my bookshelves. There's certainly not room to add another hundred or so books to my house every year.
Large print books for the visually impaired are expensive and the range is restricted. With Kindle someone with bad eyesight has access to the same books as everyone else, and doesn't pay any more for them. I don't have to read large print books, but even with only minor short-sightedness so far I appreciate the ability to tweak the font and spacing to what's compfortable for me.
I haven't stopped buying paper books, by any means. Some books are things of beauty in themselves that I want to own for those qualities as much as for the content. But for most fiction then what matters is the text and the Kindle gives me that just fine and once I'm into the story it makes no difference to me that I'm reading on a screen, or pressing a button instead of flipping a page.
The range of books available is fantastic. Okay, so you can order books at a book store if they're not on a shelf. But how, at a book store, could you, for example, compare samples of several different translations of a foreign language book, to see which one you prefer? They've probably only got one version of the book, so that's the translation you're lumbered with.