Skins change the character theme. And are rarely contradictory of the character theme anyway.
Like, Junkrat completely fits in his Jester or Scarecrow outfits. They feel like the kind of things he would wear on a particular mission that required them.
Other stuff changes the character WITH the skin. Like Tracer gets the voice line "Wanker" when wearing her punk outfit, or Mercy adds "....For a price" to her usual "heroes never die!" quote.
So the skins are fine. But a gold gun on a junkrat doesn't seem to fit with anything. Maybe one of the Jester outfits, if we assume he's a high Jester to a king of something.
we need to play together. i wanna show off my gun to you and drive you nuts.