Comment by weare138

This fact is important, because if an app were accessing a microphone and sending the audio to a cloud server for analysis there would be detectable traces of data consumption.

Because that's not how it works and companies like Meta know this when misleading it's users about their privacy.

Speech-to-text transcription is handled on your device. They never transmit the raw audio, there's no need to. A compressed text transcription of your conversation would only generate a few kilobytes of data. You would never notice it.

And the mic needs to be active in order to receive legitimate voice commands. If it can respond to your voice, the microphone is on and listening. That's the only way it can work.