Library binding is a way to increase the life of books and periodicals used in libraries. This is done by sewing the pages in place and by reinforcing the spine for each volume. The goal of library binding is long-term preservation. However, library bound books also benefit library patrons because they ensure that the volume in hand is complete, as well as to make the volumes easier to open and photocopy.
In addition, many libraries re-bind damaged books in library bindings regardless of whether they were originally paperback or hardcover.
And per a book bindery source:
"Library Binding is hard cover with a Buckram cover (Library grade vinyl), more or less an Industrial grade binding made for several uses. Not fine leather or cloth, which is more delicate."
I just ordered Hiawatha and it had no dust cover - was library bound - it was disappointing but it feels plastic and looks cheap compared to the old version. It only said hardcover when I purchased it so I don't know where to look to see if it is a library bound harcover.
I want to actually purchase a hardcover, but instead of a hardcover option, I am forced to pick paper back or library binding. So I do not think it is an option to pick library binding after picking hardcover.