I wonder if that box has been arranged to drain...

Was this part of the building automation system?

It looks like they originally designed the job as electronic with 4-20mA control signals; and somebody wanted to save money by installing the old-style pneumatic control system.

Nice

Looks to me that they used the box as a bracket for the pipe maybe?

3/4" threaded knock-outs would be perfect for a 1/2" pipe. It does appear that the weight of that pipe is resting on the box.

I did something similar to this in my house, using a 4x4 blue box to hold the hose bibb water shutoff valve. This way, it's flush-mounted inside the wall, matches the rest of the receptacles, and only cost $2.