If you drew both brushing processes as a UML diagram the variance would be trivial

Now compare that variance to the variance options given with machine and computing UX options

you’ll see clearly that one (toothbrushing) is less than one stdev different in steps and components for the median use case and one (computing) is nearly infinite variance (no stable stdev) between median use case steps and components.

The fact that the latter state space manifold is available but the action space is constrained inside a local minima is an indictment on the capacity for action space traversal by humans.

This is reflected again with what is a point action space (physically ablate plaque with abrasive) in the possible state space of teeth cleaning for example: chemical only/non ablative, replace teeth entirely every month, remove teeth and eat paste, etc…

So yes I collapsed that complexity into calling it “UX” which classically can be described via UML