Do you usually purchase digital or physical books? Why?

I'm old fashioned so all my books are physical for now. I used to hate on ereaders (first Kindle), but as I'm older, sight gets worse, readers get better (hopefully) and space is also an issue I'm already thinking of buying one. But which one? That is the question. I'd prefer something simple, without online nonsense, where I can put my files too (e.g. local library puts out PDFs of royalty-free classics for free).