FWIW, the motor is essentially directly aligned with the rear wheels. This helps. Winter tires would help more, but especially when new, the all-season tires are often adequate; not the best, but adequate. Nothing beats a purpose built tool for the specific conditions, and with winter tires, that's not only the precipitation, but the temperature which affects the rubber's ability to grip since it gets stiffer and can't conform resulting in less surface contact area.
2011 535i x-drive GT, 2014 i3 BEV