You've understood it well

By weapon artifacts i meant holy weapons skins, just forgot how was it called
As for skins/costumes or looks in general it isn't their strong side (like they would have one

). I myself avoid using 1 handed mace and off hand because i don't like to mess with stats that much.
Personally i'd love to have all the looks/skins for weapons that had been made throughout the whole game available, so i could choose whatever i like whenever i want, for free of course or as a reward for an achievement. Mainly because if you don't have a holy weapon now your weapon looks like a toothpick if you use twohanded spear. PLEASE DON'T MAKE IT A CS THING!
You've got my full approval if you need one to send a ticket