If it's a case of beng able to choose between PDF and other ebook-reader-friendly formats, then sure, but very often there isn't a choice.
Many books bought from independent authors are PDF-only.
The main thing for me is that I have a lot of documents I've scanned myself because there's no electronic version available. Handwritten journals, magazine collections, books by sluggish publishers... I'm still hunting for the holy grail of resolution/contrast/something to make my scans anything other than wispy blah using the Kindle firmware PDF viewer though. I just wish that rebooting into Duokan didn't take so long.
