argument clearer if it just said "it's a flow meter for money" then you can analyze that and see if it makes any sense. Can't say it makes sense for me. Maybe it makes sense for the banks, but not the person with the mortgage.
But even then, a flow meter exists and works by physical laws. The device and the contract are separate. A mortgage is an abstract agreement that works because we simulate its dynamics (well the bank does). The device and the contract are one and the same.
all analogies, metaphors, and similes will fall apart at some point as the two things being analogized are not exactly alike (otherwise there would not be any need to analogize)
