What you want to control is water temperature and (separately) water flow rate.
Two taps let you control those but only by guessing the right combination of settings with trial and error. On your first try you’ll get one right (the flow rate, say) and mess up the other one (the temperature, say). Try again and you’re a little closer, but not perfect.
One-handled taps align their control vectors with the search space’s basis vectors. You want more flow? Turn this way, exactly to the right setting. You want higher temperature? Turn this other way, orthogonal to the first, without altering what you had set there. There’s no comparison.
That’s all well and good until a shitty design has 3/4ths of one of those dimensions functionally equivalent, so you end up struggling to find the correct combination anyways because 90% of the useful range is spread over 5 degrees of motion.
Also, water pressure is a non-issue for how most people shower. No one is choosing 72.5% water pressure, so it’s a bit pointless to herald the separated control as much of a functional win.
So with the plethora of shitty designs out there, and the fact that one of those variables doesn’t really need to be fine tuned… I functionally agree with the other person: Combined sucks in practice, regardless of how neat the concept is supposed to be.
On the contrary, they’re brilliant design!
What you want to control is water temperature and (separately) water flow rate. Two taps let you control those but only by guessing the right combination of settings with trial and error. On your first try you’ll get one right (the flow rate, say) and mess up the other one (the temperature, say). Try again and you’re a little closer, but not perfect.
One-handled taps align their control vectors with the search space’s basis vectors. You want more flow? Turn this way, exactly to the right setting. You want higher temperature? Turn this other way, orthogonal to the first, without altering what you had set there. There’s no comparison.
That’s all well and good until a shitty design has 3/4ths of one of those dimensions functionally equivalent, so you end up struggling to find the correct combination anyways because 90% of the useful range is spread over 5 degrees of motion.
Also, water pressure is a non-issue for how most people shower. No one is choosing 72.5% water pressure, so it’s a bit pointless to herald the separated control as much of a functional win.
So with the plethora of shitty designs out there, and the fact that one of those variables doesn’t really need to be fine tuned… I functionally agree with the other person: Combined sucks in practice, regardless of how neat the concept is supposed to be.