Is it worth to take a PhD in Library Science?

I'm a librarian and I enjoy giving my contribution to the academia and, generally speaking, the world of knowledge, by providing bibliographic support as a librarian. I think that Library and Information Science is a discipline which requires a strong theoretical framework and a constant empirical analysis of what happens "in the real world" - it is a 100% social science. Nevertheless, I have the impression that research in the field is useless if it's not applied in the daily job, being librarianship something practical. Do you think it makes sense to take a PhD in this subject, or would it be more worth to just practice as librarian and do research on the field in the same time?