Okay the ignorance on display is quite amazing so in a slightly more complex but still laymans' terms kind of way
Tiled rendering works on a far more complex basis than simply swapping textures. The technique in basic laymans' terms is not a case of rendering what is in front of a player, current games do this it's called immediate rendering and that works by rendering EVERYTHING in the viewable scene weather you can actually see it or not, the distance the object is from the player will determine what texture quality is used and as the player moves closer the texture is swapped between crap quality and higher quality, this is what a lot folk here are mistaking for tile rendering.
Tile rendering takes the viewable image, splits the image up in to separate tiles and then the system works out EXACTLY what can be seen by the player in each tile, it will then render ONLY what can be seen. For example I am standing in front of a building, current techniques would have the building rendered as well as EVERYTHING in my FOV behind the building (this is immediate rendering or brute force rendering and is pretty much the main stay for game rendering as it sits) Tile rendering on the other hand would render just the house and everything behind the house would be ignored, since I can't see the stuff behind the house their is no point in it being rendered. It is far more complex than simply swapping textures in and out.
The reason why it is not so commonly used is because it is quite a complex system requiring some very intensive algorithms to get right, the fact that Power VR have been working on this specific technique since it first appeared back in the Dreamcast is the main reason why it is Power VR or variants of that appear in just about every smart phone. The benefits are very obvious, you can get more intensive graphics out of far less powerful GPUs, you can also have less on board memory since only the viewable content is being stored rather than potentially EVERYTHING the player could see.
As for the XBone 180 using it, well since it has been the mainstay of weaker end hardware too see the technique being used on a next gen console, well it could potentially deliver some very powerful graphics, the main concern being that MS hasn't done anything with Tile Rendering since Talisman way back in the mid 90s so how effective their programming is could prove to be very interesting.