Today Valve announced pre-orders for some of their upcoming hardware which includes the Steam controller, Steam machines and the streaming Steam link device.
The only reason you might think about using a Steam controller with Cities: Skylines is if you want to take the game into the living room and play it on your TV. If that’s what you want to do then you can as demonstrated in a new video from Valve.
Cities: Skylines appears to work quite well but it’s hard to tell unless you try it for yourself. However, Valve reassure PC gamers that “The Steam Controller lets you play your entire collection of Steam games on your TV—even the ones designed without controller support in mind.”
Sounds promising and may be worth a look when they eventually arrive.