Minor for some, major for others. And it is technical too, because there are maintenance ramifications for it not being in the mainline kernel, for example how

Minor for some, major for others. And it is technical too, because there are maintenance ramifications for it not being in the mainline kernel, for example how quickly a security patch can be applied. And for others a constriction on which distribution they can move to etc. It just reduces the number of situations where it can be used, even if you find yourself in one where it can.