This is a terrific way to get students using the online catalog. We spent time before they began letterboxing simply talking about how to access the catalog, how to search, and what the call numbers meant. But the best way to learn was just to do it. An activity like this allows me to assist students as needed and do any reteaching necessary.
In the end, most students have a good understanding of how to use the catalog and are ready to use it pretty independently.