The tech might not be ubiquitous now, but it will be fairly quickly.
Let's put it this way: my TV is a hand-me-down, HDReady LG 32" LCD which is approaching a decade old and really rather showing its age.
Connected to it I have a Blu-Ray player with built in SmartTV functions.
It cost me £80. The same price I paid for my first DVD player, eleven and a bit years ago, around the time when DVD was finally starting to get real traction in the marketplace, and "it's a cheap and easy way of getting a DVD player... oh and it also happens to play games" was no longer a valid reason to buy a PS2.
If the XBone costs less than five times that amount at launch I will be very surprised. If it costs less than four times, shocked. It's certainly at least five times the physical volume of my device, and probably consumes a lot more energy and makes more noise.
Or in other words, anyone who wants to be able to hook their TV up to the internet can already do so in a much cheaper, convenient, and general-TV-watching manner. Either they have a set with the functionality built in, or they can buy a cheap add-on box (if they already have a Blu-Ray player then "straight" SmartTV boxes are even cheaper than mine was), or maybe they have an XBox 360 already with XBMP installed.
If you have it already, you don't need the XBone.
If you don't have it, and you buy an XBone with SmartTV functionality as the main reason, you're a mental.
Does the thing act as a Tivo or something, then? Can you use it as a PVR, download things from the intertubes for offline viewing, record stuff to HDD from aerial/cable/satellite broadcast or whatevs?
Cuz unless it comes with some serious added value that justifies building that stuff into a separate games console, it'd be like buying a full food processor just to make smoothies, when smoothie makers are a well established market segment. I'd prefer that they stuck something more useful in there, like the ability to use it as an actual computer for the random occasions when your fondleslab just can't cut it for writing and printing a letter or what-have-you.