Wow! I might have to look into this for people who want to call me. There are always some of them -- medical places returning calls, that sort of thing. I've moved a lot of them over to email but there are some holdouts. If they could call and leave a voice message and Google transcribed it, that would be very nifty.
(I can call people via relay, and they CAN call me back via relay -- I have a special number for it. But I have to be logged in and have the screen open to get it, there are no messages. So it doesn't work unless it's been pre-arranged.)