[CanAutM3]

I's say it is cost and buyer demographics.

In the case of BMW, they are moving more towards mass market for the M line up and less towards catering to the niche of enthousiats and track rats. It's all about profits and seizing the opportunity.

DCT is lighter, has less rotational inertia, less loss, more direct shifting and better feel than 8AT. 8AT is smoother at lower speeds and is cheaper due to volume distribution.

If you look at the higher end sport car market, they all have DCT, there is reason for that. Even MB is putting a DCT in their upper end AMG GT. Porsche have DCT in their 911 and Cayman/Boxter, so do Ferrari, Lamborghini, Buggati. Of note, MB have never used DCT in their mid-size and large sedans and coupes.