I thougt I read "with intention of getting underway" or something that implied we "shouldn't" just drop the parking brake to start the clock if we aren't about to push.

I'm also sure that's not how things will be done or how things are done elsewhere, and I'm sure the company is aware of that.

The brake release and door closed helps everyone's on-time departure numbers (ramp, gate, aircrew, company). The customers couldn't care less about an on-time departure, as long as we arrive on time or early. It's really a stupid metric they focus on.