a couple of nice ones that require using expert mode is turning off the amber side markers so they act as just blinkers, brake force display (in US only iirc) so in ak emergency braking situation they will flash to alert the driver behind you. and another one I've seen recently is being able to enable B&O DSP if you have the HK sound system. besides those, personally I have not found alot of reason to go into expert mode, but everyone is different and their are so many possobilities. have you looked at the coding cheat sheet?
https://f30.bimmerpost.com/forums/sh....php?t=1020138
hope this helps