Smart TV sets are listening to every word being said in front of them. Also do other smart devices that do take action or give you information based on voice input. These device don’t differentiate between a private conversation or a voice comment for them to take action upon. They will capture all nearby sound and conversations.
Also these devices tend to capture other information, like the music you listen to, movies you watch, could figure out when you are at home, do your dishes, go to bed, have sex….
All information so collected, including sensitive data, is then sent to servers and shared between the brand who produces the device as well with third-party services who do the data analyses.
To refrain: all your spoken words, conversations, include personal or other sensitive information, that information will be among the data captured and transmitted to a third parties, where you have absolute no control what happens with the data.
How would you feel if, day and night, there where a few strange people in you house listening to everything you said. And do with that information whatever they want to do with it. That would be an awkward situation, nobody would like to deal with.
I think its smarter to refrain from using smart devices, until they deal in a decent way with privacy.