Can you trust a smart speaker?

(A) Yes. I think smart speaker is a convenient device. I just give it a voice command, it does everything I want.

(B) Smart speaker like the Google Assistant, Amazon's Alex or Apple's Siri. When you give it a voice command, it can search everything you want.

(C) Smart speaker is a listening bug.(When you say something, it will search the data and give you responses, but is not safe.)
And while the companies say they are only actively listening to what's going on in your home when they hear the keyword, the microphone is still on the whole time in order to be able to detect the keyword.