I too would have said my nano/shuffle back in the day. Yeah wearing corded earbuds was somewhat annoying. But they were GUARANTEED to work. I have a few pairs of fairly high-end Bluetooth ones and I find I have to re-pair them every once in a while or they just lose contact with my watch mid-run, which is super frustrating. Not to mention the interference with other Bluetooth devices such as when you're at the gym.
And I know I'm probably about the last person who cares about this. But we have a really good FM sports/talk radio station where I live that's still very much worth listening to. And not having a cord (antennae) means no radio when running. And no, I'm not paying for LTE on my watch just for that.