It is really quite simple.
If you believe scale swill help you improve and/or you enjoy them then go ahead and practice them
If you believe they are unnecessary then don't practice them
The proponents of either of these points of view can try to browbeat holders of the other to agree with them forever, but they won't succeed. Why should they? There are top level performers in each camp.
But ...
If you want to take AB exams up to Grade 8 then you'll just have to play by their rules and learn them (at least well enough to scape a pass) whether you like it or not.
