Certain ads will allow you to interact with them via your microphone for hands free driving or whatever. It's new and you'll probably start seeing it more in other apps but this is the first time I've seen it in an app.

To all current and future app developers using microphone-ad-interaction: die in a fire.

The app does not need microphone access. You know it, I know it, NPR knows it.

It has xapp ad integration, which requires microphone access.