IMO the biggest utility of a headphone jack is not for earbuds, it's that it enables you to play music from your phone on basically any device made in the last 30 years. Want to hook up to some random stereo? No problem, you can do it. Want to play music in your car, but you have one of the many cars without Bluetooth? Easy. There's a lot to be said for having a damn near universal audio connector. Bluetooth is nice, but it's not there yet in terms of ubiquity.

My personal use case for the headphone jack is playing music in my car. My car doesn't even have an aux input (I have to use a cassette adapter), let alone Bluetooth. And when I'm on a long drive, being able to play music while charging is a must. I will only very rarely hook up a pair of wired earbuds to my phone, but I absolutely must have a headphone jack.