I see a lot of people complaining that the Fairphone 6 doesn’t have an Aux jack.
Just use an adapter cable.
A 3.5mm Aux jack takes up a significant amount of space just to connect a few wires that could be connected through USB-C anyway, that space could be used for a bigger battery.
Even if there was a good enough reason to keep Aux it should be 2.5mm Aux and not the usual 3.5 as it does exactly the same thing but uses less space
Admittedly I was very stuck in the ‘I hate phones not having Aux’ camp because I preferred wired headphones for the longest time.
I was given some fairly poor wireless headphones and was pleasantly surprised by those, so I bought a good quality set myself. Now I’ve gotten so used to being untethered from my phone while listening to music, or podcasts, etc that I don’t think I’d go back to wired headphones while mobile.
That just leaves stereo systems, portable speakers, vehicles and the like. All of those, instead of carrying around or leaving an aux-aux cable, swap that for a usb c to aux cable.
Or even one of these:
As OP said, more space for battery. It’s also one less opening to waterproof. It took me a good long while, but I’ve come around to agree a headphone jack just isn’t worth the extra space it takes up. It’s not worthless, but there’s better ways to use the space.