This is a feature that I've been craving for some time. I would upgrade to Premium to get it. Didn't know that OneNote already supports this; if the feature works on iPad I'll be switching, at least for meeting notes that I record. A transcription feature would be equally useful, especially if the transcription had clickable timestamps embedded periodically (say every one minute or so).
Also, the new ability to add audio recordings to existing notes will be useful for me. Thanks for that!