I've read an article that they were about to get a lot more common outside of the US.
Apparently they can better "tune" emissions that way and since there are heavy fines and a lot of control going forward that's the argument they are using.
Also apparently manual gears are more expensive to manufacture, I think.
Again I read this on an article sometime ago so it could just be BS, I can't seem to find which it was.
Imo, they just want to greenwash this change. In reality they can save money and improve scalability and just standardize everything.