You're already buying a skin for 20 bucks or way more if it's a knife skin but you also need to have a different currency to actually use the full skin. And that currency is not really easily accessible: A small amount from the free battle...

I find it unbelievable that you cannot choose on which lvl of upgrade your weapon skins are. For example you buy the elderflame knife and want to go without the flames for whatever reason. You cant, even though you paid a hefty sum you can...