Yes this approach is great. Everybody is being paid, and you have the freedom of multiple formats. No one is getting screwed, because no one expects people to buy books in multiple formats (except perhaps audiobooks, which are different because you also have the reader who deserves to be paid). It would be nice to see publishers embrace this sort of flexibility (e.g. with a download code printed in the book?), but the use case might be quite niche for most readers so it feels unlikely.