I find I’m much less likely to finish a book on Kindle. It somehow seems less important than a physical one. And the number of pages left varies depending on how big you have the text, which is confusing. Whereas with a physical book a page is a page, so if you’ve only got 20 to go you can usually push through to the end.
Books are my final holdout against digitisation. Everything else I’m fine with digital versions, though I still buy vinyl versions of the best 10 or so albums of each year.