I think there are also acceptable trade-offs.
The video is encrypted and content from the call cannot be used. If this was not the case I wouldn't buy it.
The other things they say they'll use from it are in line with what I already expect from having a FB account in the first place.
The portal even has a built in camera cover/off switch in hardware.
The other component is apathy, many people are just resigned to the fact that they will be surveilled one way or another.
I can foresee huge implications for all of this, it doesn't take much to get from here to using these devices to aid law enforcement. I know the argument is 'if you have nothing to hide... it keeps the kids safe...' but it all smells of a conformist dystopia.
Edit: I have a bunch of Google Homes, I count myself in the apathetic group, sadly.