Hotline, I wasn't referring to a one-off 'field evaluation.' I was asking ... what's really wrong here?

I'm a bit disappointed in the lack of thoughtful replies. Maybe I should give it a try ...

Code already requires the pipe ends to b free of burrs and sharp edges.

Let's look at that shower arm as if it were any other piece of conduit:
OK, I see threads. Would it pass muster as IMC? After all, there are strength and wall thickness requirements for IMC.
There's also a minimum bending radius. Does this comply?
One difference between plumbing pipe and electrical pipe is that the ASTM standard specifies that the inside of electrical pipe be 'smooth.' In practice, this means that the lengthwise ridge formed when the pipe was welded together has been removed. What does the inside look like here?
I expect the plating does give enough corrosion protection.

What about copper pipe / tubing? Well, if you look at the relevand product standards, there's always room for alternative materials of similar strength. Maybe one of the copper tubing grades would pass muster as EMT.

A problem arises with the fittings, as code tells us we cannot rely upon solder alone for our connections. Now, if they used an old-style 'dimpler' together with solder, they'd be good to go.

Let's look at that Bell box. First off, what's to keep the connection from coming loose? I'd want to see a locknut there.
Just as important, code requires the box to be supported by at least two conduits, where conduitprovides the support. I only see one.

Open KO's, etc., are issues that would apply to any installation.