FLV is a relic of the Flash era: the format YouTube grew up on, stranded when Flash died. It was born in 2002, Macromedia (later Adobe), for Flash Player, and its real weak spot is playing anywhere at all since Flash was switched off in 2020.
Whatever the recording, audio just wants to be heard: the trick is picking a shape that plays where you need it. Stands in for any audio format Flippy can read: MP3, WAV, FLAC, AAC and friends. That makes it the right destination when what you need is any sound file: music, voice memos, podcasts, session exports.