They want you to buy their crap. That's it! It's all about separating you from your money. Nobody cares about you for any other reason. We just aren't that important. Does anyone on this website actually think the freakin' CIA cares about the latest fight you had with your wife??? It's the height of narcissism.
(When I used "you" in this post I was not talking about you personally.)
As for government and/or law enforcement... A definite maybe. I have no doubt if there's information they can access without a warrant, they will pull it together looking for crimes to prosecute. This is similar to how lawyers tell us never consent to a search. We are innocent until proven guilty. The only thing a search can do is turn up evidence to change that. Same thing with this voluntary search/surveillance.
I have no delusions that my life is interesting enough to merit attention from government or law enforcement. If they have nothing better to do than look into my life, I genuinely feel sorry for them, but also believe we should trim their budgets since they obviously have too much staff, too much time on their hands. Funny sidebar - I like to sing along to classic rock in the car while I'm driving. I have a terrible singing voice. Terrible might be too kind. Occasionally as a joke I'll say out loud something like "To who-ever is listening, sorry, I'll buy you a beer sometime..." Now, if I'm ever sitting in my favorite brew pub and a stranger comes up to me and says "Say, how 'bout that beer you promised me the other day before you butchered that Rolling Stones song?" I'll definitely freak out...
Seriously though, it goes back to that consent to search. If for some reason I ever do come to the attention of some government agency and/or law enforcement, I don't want to have already put out there all kinds of information - who knows what things like this fb device, Alexa, Kinect, etc. are collecting, how it is organized, how long it is stored, and how well it is secured. I don't want to find out the hard way.