Curious Kohler Spaghetti Piping Arrangement

This is in the same house as the "Multiple Shower Issues" thread. That shower is in the guest bathroom.

We have another shower in the master bathroom, which thankfully works okay but with some quirks of its own. It can wait.

The master bathroom also has this jacuzzi tub, which also works. But the previous owners, who lived there for ten years before us, informed us the handheld shower faucet was never connected.

Having seen the condition of the shower valve in the downstairs guest bathroom, I was skeptical. I'm thinking this valve is probably just corroded too.

So my first question was, how the heck do you even get at the plumbing for this tub as it's all encased in marble. Yesterday I finally got around to lifting the tiles in the drop ceiling of the downstairs room directly below this bathroom and discovered, it's true.

That handheld shower faucet is currently not connected to the plumbing at all. But there sure is some interesting piping under there...

Accessing the pipes is a bit of an issue. I managed to reach up through the hole in the ceiling far enough to get my cellphone in there to snap these photos. But otherwise I might have to hire a midget if I ever actually need to get at the pipes.

The good news is that both the Hot and Cold water feed pipes have individual shutoff valves. That's a good start.

The feed pipes go straight up to the Hot and Cold handles on the tub, and there's a copper pipe leading to the tub spout. But what's off to the left where these pipes curve away to?

That's where it gets interesting.

That octopus on the left is connected to the braided hose leading to the handheld shower faucet. But that's all.

Even though it's spouting several pipes off in different directions, none of them are connected to the house water supply.

After some online searching, I think I've identified that nifty valve, to activate the handheld shower, as a Kohler Bravura K-6949-LV-CP 3-Way Transfer Valve/Vacuum Breaker.

I'm just guessing here but, rather than joining the outputs from the Hot and Cold directly to the tub spout, shouldn't those have been routed through that shower valve instead? That way one could choose to send the water to either the shower handle or to the tub spout?

Why would anyone install something like this but not connect the pipes?

Can anyone confirm whether I labelled these pipes correctly?

That transfer valve must have quit working and instead of trying to fix or replace it they just did away with it.

Or, more likely...

Maybe that shower valve is buggered, and rather than fixing the valve they just cut it out of the circuit altogether and instead plumbed the water directly to the tub spout.