This means you can’t buy Xbox 360 titles or their DLC on your Xbox One.
The New Xbox One Experience is rolling out today for the Xbox One, which brings a faster interface to the console and a bevy of new features including backwards compatibility for Xbox 360 games. Microsoft made sure to clarify some aspects regarding backwards compatibility to Game Informer and it revealed that you can’t purchase Xbox 360 games from your Xbox One.
As a representative stated, “Right now, Backward Compatibility does not emulate the Xbox 360 store [so] new Xbox 360 games [must] be purchased on your Xbox 360 or via Xbox.com. DLC will be supported and automatically downloaded to your Xbox One along with supported games.
“We will support both digital and disc-based entitlements for Xbox 360 games running on Xbox One…Provided you own the DLC already, you should be all set once the service launches widely on November 12.”
So essentially, you need to hop on your PC or Xbox 360 if you want to buy digital versions or DLC of your favourite games. Expect backwards compatibility to go live at 12:01 PM PDT/3:01 PM PDT later today.