It's just too far from standard page sizes to do them justice. (phys.org)
If you just use a blank document set to the correct page size, however, and try to upload it when you're finished, it won't work well. (hubpages.com)
You've found one of the things paper books do better than ebooks: the impression of value for money by page size to the browsing buyer. (madgeniusclub.com)