Why would they need to listen? That's a lot of processing power

But... why would they care? It's your energy bill, not theirs.

I think about this every time I see a random thing I have never heard of before and go to search for it and autofill has the exact phrase I wanna search after typing only 1 or 2 letters. It either reads text on the screen or listened to me say to myself "what the hell is yadda yadda?" because how else would it know I had a really good chance of searching "what is yadda yadda" after only typing "wh?" The yadda yadda part could have been anything, but it still managed to predict the exact thing I was gonna look for.