It's beyond odd; it's simply idiotic. You would not "buy down" holds for physical books, or not to a ridiculous degree. If there are 100 holds for some book, you're not going to go out and buy 75 or whatever. Why do it for e-books? Cause, wee, they don't take up shelf space in the stacks?
If a book is popular, let the patrons "buy down" their own copy, or else wait behind 90 other people.
There is always bittorrent and filez websites: the real libraries of the digital age.
There are also ... craploads of other worthwhile books you could explore that are not held.