As to the 'why" it is the latest and supposedly "greatest" in a long line of fads.
Run your AR wet with good quality lube and it'll run if it's high quality and to spec. If it's low quality and out of spec, no fancy lube will make it run.
I've seen the fads run from Break Free to Vagisil to white lithium to grease to 30 weight to militec to whatever. Most of these lubes are designed to part you from your money. YMMV.
"Every man dies, but not every man lives." William Wallace, Braveheart......
I will not lie, cheat, or steal. Nor tolerate those who do.
God is so good to me.