I have a Bluetooth receiver for my hifi at home, a Bluetooth speaker in the bedroom and multiple pairs of Bluetooth headphones.
However our new car does not have any kind of Bluetooth integration - only an aux port. It is this kind of scenario, where the only option is a wired connection (without buying a receiver of some kind), which means the removal of the headphone port is particularly annoying.
I use a Taotronics Bluetooth adapter in my car aux port and it works well. Might be worth a go.