User blog comment:Mineko Charat Lucky/Ward skins, why doesn't Riot expand on them?/@comment-8234800-20130415181920

Summoner's Rift is by far the most popular map/mode of LoL, but still, every single other map (3v3, Dominion, Aram) doesn't have wards. While champion skins can be used on any map.

Just saying, Champion skins probably make much more profit.