While the upfront cost is higher, the ebook:
*won't wear out
*won't be stained
*won't have its binding be broken
*won't require stack space
*wont require inter library transfer or home delivery
*will be lent out in much greater frequency than paper due to the ease of download and notification of availability
It will require libraries to be more picky about what they buy but i'm not sure that is a bad thing.