I understand that if I do a Book search, it will limit to my library whereas an 'All' search includes unlicensed resources. I think this is great and can aid in the discovery of new resources. That being said, results from licensed resources should be prioritized over unlicensed ones.
I have a 'sizeable' library and with the ALL smart search, I was still finding licensed resource hits after multiple 'more results' even though there were only a couple of hits initially. Even on the initial results screen there were 6-8 unlicensed hits prior to the first licensed hit even though I would have considered those first few licensed hits to be comparably good when compared to the unlicensed ones.