Another 2 points to potentially leak with that method though.
Although it's potential it's very unlikely. They are npt threads and when correctly assembled the chances of leaking is remote. Same as the oil galley plugs in the block, the oil pressure switch, etc.
Anyway just a thought.
Since coming across this thread I've now seen three different ones made from metal. The two are three piece with the barb fittings brazed or welded in, one with threaded holes.
I think the biggest advantage of the three piece unit is that anyone with a good lathe could make them. May even have a go myself with my little hobby 7x12 or maybe go and use the neighbours big old industrial size machine.
Obviously a cnc lathe/mill would make it much easier for repeatability and quality control.
