OK, I'll leave this thread here for future searching newbies like me, and for educational replies, but here's at least one answer found on another forum:

https://www.muffwiggler.com/forum/viewtopic.php?t=43964

Oscillators send a signal even with no input. even if there's nothing saying what pitch to play or when to start/stop - that is done by other modules such as sequencers, VCAs etc. This is true for VCOs - they'll make a constant tone and LFOs - they'll make a constant CV (dependent on settings)

Apparently, oscillators don't always oscillate, and perhaps they're the conventional way to get a constant CV, e.g., for a static setting on a CV-controlled pan: oscillator -> attenuvertor -> pan.