I would prefer 3.5mm over Bluetooth, but keep in mind most people get their music off their phones and (almost?) no modern phones have headphone jacks. Dongles are a thing, but meh.
Additionally, modern Bluetooth devices have very little friction in my experience.
Ye. Many modern phones are *@*$ too. My wife is still bitter about not having a 3.5mm jack on hers she unknowingly bought 5 years ago. So much trouble ...
However if more than one person will use the car (incl. as passanger) the annoyance of Bluetooth is even worse.
We have a dongle in the car that is protected by a sworn oath to never be removed from the cabinet along with some charger cables.
Multi user seem to be the major pain point. I think linked and active headphones blocks the car too.
There is just so much stuff that can make the abstraction of automation leak and you have to spend more time fixing it this one time than saved in the total lifetime of the car with a simple cable.
Additionally, modern Bluetooth devices have very little friction in my experience.