Except that the entire point of the valve-drill is (was?) supposed to allow the diver to "get" the connection between right/left posts and regulators (i.e. the act of breathing down the regs drills into you what regulator is attached to what posts)
Seems like you lose that correlation here and a lot of the benefit. No ?
I see your point there, hadn't thought of that. Was only thinking of not lugging all that weight around the house to practice.