even if the man can make diamonds?
I am pretty sure that even on rog-war's planet, gems are of value, and in the junkyard they are even more.

and if he finds Volray, he will find black and other type of crystals scattered, then a man in a crystal made broken armor and the man is part crystal himself
I guess even Nex would put one and one together and protect/ aid the man just for the chance that the man can make him very rich, and he is more animal then man XD