I think it might be slightly annoying to have a two-inch-long dongle hanging off your phone at all times, particularly on a brand of phone that's specifically marketed (and purchased) for being sleek and clean-lined.
Until you want to charge and listen to music at the same time, which I wanted to do on a flight recently. I had to charge up to what I thought was enough and then put the headphones in. Annoying.
My wife also brought Lightning headphones, which didn't work with anything except her phone, leading to her using the cheap airline ear buds for the in flight entertainment system.
