The reason skin splash arts are not displayed in game on icons is because it would cause confusion
The game is so unwelcoming to new players that I'm not sure why we consider them there.
There are many skins I've purchased for the splash art alone. Arclight Vayne has an amazing splash and a lackluster model. Battleborn Kayle.
I'd like to use the skin splashes in game. The ultimate skins get it. Is there a real reason others don't?