“apps” is a good metaphor because norns scripts are very like apps that run on your phone: they are sandboxed from each other, and each one is allowed to make use of the entire available system resources while the app is running.
but norns scripts differ from “apps” in that they are very easy to make. so if you want to modify the internal routing of musical logic you can do so easily by editing the script. (and many scripts include modularized components to make remixing them easier.) to modify the internal routing of audio, or to add effects or whatever, you can edit the supercollider components, and supercollider is a good thing to learn anyway if you’re into digital audio.
the belief that programming environments are more powerful than patching environments [*], is central to the design philosophy.
[*] that is, for this kind of minimal-UI-computer system.