Indeed, privacy! My doctor called the other day needing some private information while I was in the office with other people nearby, about to start a meeting. I couldn't leave the room to answer her and with my umming and ahhing she cleverly surmised I was unable to talk. Wanting the information quickly she turned to yes/no questions and got the info she needed. There's simply no way I'm gonna talk into my phone "Hey Google, renew my prescription for highly sensitive medication on the bus or anywhere outside the privacy of my own home.