n2596s
It took me a while but a bit if digging about in the Boeing 787 flight manual and I find talk of Left And Right ADF and how to display the bearings.
Clearly it is a Boeing option and is likely to be chosen by those who need it, this seems to be reflected by reports that BA are not supporting ADF on their A320 fleet ( I shall check this ). BA are a Big airport operator and don't go to the smaller Southern European holiday destinations and so ADF is likely to be of limited use.
As the B737max has a lot of B787 technology I would expect ADF to be an option for those customers who want it.