Headphone jack. Next to my bed is the one good Bluetooth headset, the two crappy backup sets for when it is charging, and the gigantic earmuff yardwork set for when the good one is still charging and the 2 shit ones have already died.
Does it actually belong in the phone? Putting the adc chip outside the phone gives the opportunity to upgrade your sound rather than depend on what the manufacturer bundled or even screwed up. (Nexus phones were notorious for bad headphone output.)