We used to have earbuds that don’t need to be charged because they had a headphone jack, didn’t get lost so easily because they had a cord attached to a headphone jack, never lost the bluetooth connection because they had a headphone jack, and they cost less because they had a headphone jack. https://bsky.app/profile/daisyfm.bsky.social/post/3l3mfjc6sn62k
That’s just power. You still need an audio connection.
Other replyer answered, it would broadcast your phones music onto a radio frequency.