It seems that even the Microsoft owned Rare development studio struggled for a while before accepting the notion of button-less gaming.
The revelation comes from Nick Burton, development director for Kinect at Rare, who "remember[s] those first few weeks of us having the tech in November 2008, we were going 'but you've got to have a button!' To the extent that we built little buttons that you could hold in your hands, just to try it."
"The acid test turned out to be a couple of prototypes we worked out quickly. We weren't thinking about sports, these were just ideas we were chucking around for three or four days at a time. We had a little goal kick game that was to test accuracy of avatars and it worked well because we could place a virtual ball in front of the player. And at the same time as that, we realised that kicking doesn't involve a button, there doesn't have to be a button press."
"That was the shared moment where we realised we don't need buttons," he added. "At that point it really evolved for us. It turns out there are lot of ways to interact, it's just a case of finding the right way to do it for your product. It was interesting at that time to go from the assumption that we've got to have buttons to the realisation we don't need them."