I can be OK with a pbook nomination - but only usually if I already own the pbook. I'm not going to try and source one just for a reading club entry. Firstly, I try not to buy pbooks anymore and secondly, I'm not a member of a local library (don't care to) and taking time out to look for nominated books in the local/regional library would be a step too far for me to bother.
However, I don't have any hard feelings about pbooks being nominated/voted in. Even with ebooks, if I really don't want to read it, a spot at the top of a book club leaderboard is unlikely to change my mind.
It sounds terribly rigid, but it doesn't mean that I don't stretch myself. Last year I read A Room With a View
, The Island of Doctor Moreau
, A Christmas Carol
, The Master and Margarita
and The short stories of Saki. None of these were anywhere near a TBR list of mine and I enjoyed them all. It helped that nearly all were free of course.