Similar to the camera interface, this is a request to auto-connect the audio-record interface for the chromium snap .
It is a pretty common use-case to do video-conferencing or other webrtc-based applications within browsers these days, and without the audio-record interface the chromium snap will report that no microphone can be found, which will lead users to report bugs because they want this feature to work out of the box.
Besides, chromium prompts for permission to allow microphone capture on a per-domain basis, so that’s an additional level of security for actual access to the hardware.