So often I get offers for bundles of books, and I might see one or two titles that I want and don't want to spend $100 for the whole thing.
There needs to be a way to mark an individual book to a wish list for Logos to notify me if this book becomes available as a single volume. In fact, doing this allows Logos to see what volumes have enough interest to make them available as a single volume.
If Logos doesn't do this, there is no way people like me are going to keep track of these books and keep on the lookout for them.