Currently you have a Pro beta feature of interactive transcript support for video.
When I put an mp3 file url in a src field, the player plays back an audio file. So I assume it supports an audio format. But I can’t check whether an interactive transcript works with an audio record since you have only a demo with a video.

If it does, great. For me, it will eliminate a need to create a video file out of mp3 record as a workaround.

In a simple case, I have 1 video and 2 audio files in a playlist to play back with an interactive transcript. So if a video plays, I can see a transcript of the video. If I switch to an audio record in a playlist, the transcript container is refreshed with a transcript of the current audio. And when I click on any line in a transcript, the audio starts playing at that exact moment.