When you walk around with your AirPods, Siri will announce your incoming messages. It's super useful, as I have a very strict notification policy. I curate my notifications to prevent unimportant ones. So every message that's announced is important.
Podimo has made the baffling choice to keep playing your Podcast while the announcement is happening. Allowing you to understand exactly zero of the two sounds that are being pumped in your ear.