It would make sense that Ninja Gaiden 3: Razor's Edge on Xbox would use Xbox Smartglass to add tablet features, since it's based on a Wii U game (that's based on an Xbox 360 and PS3 game.)
However, the Smartglass features are different from the inventory and off-TV play features used on the Wii U. Playing with the SmartGlass app loaded up on your phone or tablet allows you to keep track of your gameplay statistics. It also allows you to load up videos on YouTube of other players clearing the area you're in, to help you make your way.
Razor's Edge will be available April 2 in North America, and April 5 in Europe.