I hope this helps, I do not wish to add to the back and forth.
Those other 3 modes people/ groups focus on for "competitive" is because most people see it as competitive. However just because that is the focus, does not mean it neglects other things. There are plenty of groups I seen here not only have a sub casual group but do fun stuff like hide and seek,brush wars and stuff like that. So these other groups do random TW matches in ww, even C- did it here and there. Sometimes tournaments and scrims do have tw maps in rotation, doing on one single aspect of the game is pretty short sided.
So you are pretty mislead if you think people only do the rank modes in clans.