@Susan1 I use a dedicated eReader not a computer, phone or tablet. No backlighting. I use one because the ability to adjust the font and spacing means I have less eye strain due to my hereditary retinal disease that may result in vision loss that isn’t correctable in the future.
Please do not judge people who use digital books. It isn’t always about space, tech or not driving to the library. Without my Kindle, I’d be lucky to be able to read even half as much as I do. Plus less eye strain stresses my vision less which is better for my future prognosis.