Why is it that when people make an assumption about the XboxOne's built in mic the assumption is often that it's going to be a PoS? I mean, you can just as easily take it in the opposite direction and assume it's going to work great.
If my iPhone can detect and limit background noises I am sure that the XboxOne will be capable of the same. You can make a case for other people being in the room and talking, but I think that's a small issue in all actuality. As for people/kids/spouses/etc. being rowdy and yelling, shouting, cussing, screaming, and crying; that kind of loud and crass stuff is going to come through a mic no matter what, whether it's sitting on your head an inch from your mouth or sitting in your TV stand.
The biggest issue people seem to have is that they don't want to communicate in a different way than they are used to. The alternative might be better and more convenient but they want to stick with what they know which in this case is a headset.
Also, this is not the same as the PS3 and its complete lack of out of the box communication, that comparison should not have been made.