Spring drive would theoretically work without the quartz components. Seeing how they would generate an electrical current because of the principle, they build a tiny generator to drive a circuit that adjusts the escapement, but doesn't run it.

Also, Spring Drive depends on a fully mechanical wheel train and barrel spring to function; it could not be made to work with a battery.

So what exactly constitutes mechanical and what does quartz here? Is it the wheel train? Does electro-mechanical count as mechanical? Is the mere presence of a quartz crystal in a secondary circuit enough to call it a quartz?

I found it easier to see it a as a new different system for timekeeping instead of trying to place it on an arbitrary scale between "fully mechanical" and "quartz."