I can't say that I was any better using the Steam controller (not that I'm any good to start with, but that's another story), but the real story I guess is that I wasn't much worse either.
I've seen some demos where people used the accelerometer to play Street Fighter (https://www.youtube.com/watch?v=D0YGzURzThY) which could open up the game to some people with physical limitations. I'm a fan of anything that gets more people into playing games.
That the Steam Controller is more customizable than a lot of controllers to me is its biggest strength. And now, with the ability to 3d print mods, I think it's even better.
Cities Skylines has tons of menus, sliders, charts, tiny checkboxes, small details to attend to and is generally uninteresting for onlookers most of the time. Even if you're just being creative without all the micromanaging, a controller still feels more like an inferior tool that stands in the way of your designs. It's just not comfortable to sit back, relax and build the perfect city. That game is much better suited to play alone at your desk with a mouse and keyboard.
Edit: sorry wrong person, but it still works as a response, so I'm leaving it. I've been awake too long.
None of my fight pads were XInput and I was a little lazy about setting up an XInput wrapper to get them to work.
The left touch d-pad is quite good for quarter and half circle motions, and dragon punches are pretty easy to pull off.
I also experimented with the right pad as buttons. It was pretty good, but where it fell short is that the right pad, unlike the left pad, doesn't offer any tactile cues as to where your fingers are.