In the same vein, I'd like to see some benchmarks with SQLite vs Cache::Cache, DBM, etc for readonly caches. Since the write lock is global, reading would seem to be it's biggest benefit. If it's faster than Cache::Cache, then you have a potential user in me. :-)
As for what I would use it for, I'd probably use it in a project like the one I'm finishing up right now. It is a simple order app with 5 screens. Currently the data is stored in CSV files & read using Text::CSV. And I'm using hidden form elements to maintain state between screens. In this case, it's not worth it to use a "real" database. And I'm not even sure they have access to one. But DBD::SQLite might be just the ticket for this instance. As long as it's simple to compile/install.