Take into mind this is a Free to play game. This means the only form of market they make is on Sales of Rp points, Items in the real world like shirts, and when they host the Championships. From a Business view they need a way to make money and Skins are the easiest way for them to make that money. I mean you have a champ you love to death. Like how I love Veigar when I first got him. You want to make him stand out. Thus you get him a skin. Something that sets you apart from the other champs if for the coolness.(Or Silliness) Of the Champ. Without the profits they make for rp points they can't fund the creation of new champs for the manhours of work people put into the game and thus it is a balance of evils. Without one you cannot have the other.