The Kinect, once a required part of the Xbox One, is no longer seen as the system seller it once was, at least not by Phil Spencer, recently appointed head of Xbox.

That's a far cry from how the Kinect and Xbox One were introduced to the world last May.

"The all-new Kinect is now an essential and integrated part of the platform," according to the press release put out at the time. "By having it as a consistent part of every Xbox One, game and entertainment creators can build experiences that assume the availability of voice, gesture and natural sensing, leading to unrivaled ease of use, premium experiences and interactivity for you."

But a year later, Spencer announced that Microsoft would start selling an Xbox One without the Kinect. Spencer told Polygon at E3 that he believes that ultimately that will lead to more Kinect in homes.

"This might seem backwards, but I believe the decision we made to allow people to buy Xbox One without Kinect included, in the end, will actually lead to more Kinects in the market," he said. "I believe that you've got to sell the console before you can sell Kinect.

"Price point is important. I had to give people a choice when they come in to go buy a console, that we have a console that's at a competitive price, that's at an entry price for them. "

And the $100 price drop isn't trivial, he said.

"I believe that you've got to sell the console before you can sell Kinect."

"We've got to be competitive with the Xbox One console, and then we're going to allow people to add Kinect later when they can," he said. "They can buy it standalone. If they want to buy it day one, I still think that's the best Xbox One experience over the long run, but giving them choice will let us grow the largest install base of Xbox One customers, and those who choose to, will actually add Kinect to it as well."

Spencer says he thinks the fact that there will be both Xbox One with Kinect and without will also be good for developers.

"Developers will choose when Kinect is part of the experience and when it's not, and that's the way it should be."

The fact that soon not all Xbox One owners will be Kinect owners also seemed to shape Xbox's E3 press conference. Kinect features weren't really talked about during the press conference, which was packed with games.

"I consciously made a point to try not to call out where every game is using Kinect in an interesting way," Spencer said. "It's a difficult thing to do on stage, and second, I think really what you want to focus on is why is a game fun, not what parts of the platform does it happen to be using or not using. A lot of those games are using voice, some are using gesture, a lot are using SmartGlass in interesting ways, but I wanted to first highlight what the soul of the game is about, which usually isn't about its platform features."

Spencer said he still gets a lot of people pitching Kinect games to him.

"I think it's great because people see it as an outlet for creativity, whether it's immersion, whether it's voice integrated in some interesting way, whether it's gesture," he said. "I think that the creative conversations I'm having with studios are more about, what is the core of what your game is, and then the studio actually usually comes to me and says, ‘Here's how Kinect's going to make that better.'

"In terms of a specific focus to say, ‘Hey, you guys, you have to do something that requires Kinect.' I'm not doing that. I'm saying you need to go make games that are great. We think Kinect adds functionality to the platform that makes games better, and developers will use that when they think it will make their game better."