Personally, I dont think its to smart. mainly because of Viruses. And i can see it now... microsoft is going to make an anti-virus program, just for those idiots who decide to watch porn on their xbox.
You can already put an antivirus on your Xbox albeit an Open Source one if you are going to look at lewd material on Internet Explorer... but the app does have good beneficial uses like those stated above and in my own experiences I can talk to friends on other forum boards with out leaving the comfort of my sofa as I don't own a laptop. And sometimes turning on the PC is too much effort.
I personally find it is a lovely addition... if something happens where someone cannot use/or have a computer, you can use the Xbox now to recruit. You can also guide them to information that they need to know right there within Xbox.