Agree but logically it does make sense (It didn’t to me until it was explained from a buddy at BMW)
5 series = 4DR
6 series = 2DR
7 series = 4DR
8 series = 2DR
So it makes sense to make the 3 series a 4DR and the 4 series a 2DR following the pattern… I would assume the 1 series will become a 4DR as well and the introduction of the 2 will come later on.