[SamReidHughes]

> Well, for one, the escapement doesn't depend on the quartz crystal for timekeeping

No, it uses the quartz crystal for timekeeping. It keeps time like any other digital watch, only it outputs that time by controlling the rotor's speed, and gets its power from the rotor.

It could keep time mechanically instead and still use electronics to maintain the rotor's speed. But in fact it uses a quartz crystal.