For the purposes of this conversation, we generally speak of the TC-ness of a system if we could somehow expand it indefinitely.

I believe there was someone who set up a TC-complete roller coaster network in some Rollercoaster Tycoon sort of game. It had something like 25-slots of "RAM". Not very TC-ish. But if you could hypethetically expand out, hypothetically it would work.

So it's a common convention.