That's probably on the other side of OPs picture

The reason we put them in the walls is so they don’t get pulled or damaged, which creates an electrocution and/or fire hazard.

When houses were first retrofitted with electricity, they ran the wires on the walls, not inside them.

As someone who just had to have a wall torn out to repair a pipe, having it on the outside would've saved me so much time, money, and damage.

Where you lost me was blaming housewives for causing pipes to be put behind walls.

My college dorm was an old stone building that had been a Civil War hospital, so it was built before indoor plumbing or electricity. Luckily, it also had high ceilings, so all the pipes and conduits were all exposed above us. There was a pipe just outside my dorm room door, and whenever I'd go out, I'd jump up and do 10 pull ups.

Coulda gone with one less hole. That's just more work.

I'd say it's a pretty solid £35's worth of plumbing