I think I can count the number of times that I've managed to get bluetooth to actually work on the fingers of one hand. It's just trash. Give me a wired connection every day of the week, and it better be something universal like USB-A, micro-usb, HDMI or 3.5mm.
Bluetooth has been better for me 80% of the time and then that last 20% is a huge pain where as AUX is consistently a little bit worse but it never totally lets you down.