We have plans for what to build with them, but we made the choice to start off extremely modular/reusable because we want to build an entire suite of clients and be able to maintain and alter them later, as a group.
Discussion
Additionally, in the spirit of contributing to the Nostr community at large, this lets us make our work available for other developers to use from the get-go. As we use it, and possibly as other devs use it, we'll incorporate feedback and fix bugs to make this foundation every more robust and stable.