Cities Skylines is a wonderful game! although i haven't returned to it since the transit dlc! I bet it's even better now!
For Steam, Users could get rewarded for their contributions to the workshop with mods and guides of the game, helpful interactions with other players, in game economies for online games, the possibilities are endless on this aspect if big MMOs adopted the system!
I also like the idea of funding game development with ICOs imagine all the crazy ideas that would get funded! a platform similar to Steam Greenlight could be created functioning similar to a kickstarter but as an ICO.