The Kindle is brilliant for travellers, you don’t have to lug heavy books around. Also, if you have visual problems, you can blow the text up really large. My DH had it set up so there were only a few words per page.
I find the downsides are with books with footnotes, diagrams, pictures and maps. Better in an actual book, especially with the footnotes where you can easily flip to the back or chapter end to see them. I tend to keep the Kindle for fiction and patronise a bookshop for the rest. I’m referring to my old original Kindle here, I don’t know whether the newer models are better.
I prefer the Kindle to my iPad as my Kindle isn’t backlit and is kinder to my migraine prone brain.