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.