They don't, though, or at least they don't now.
I did the same double take. There was absolutely nothing in the main rulebook to make you think mystic adepts couldn't normally take masking, etc.
But here it is, the 20 pt quality (after paying for power points! So it's really going to be 40 pts post char-gen) yelling MAs they better take it or no masking, etc.
Very backward way to insert a rule.
Not that any MAs going to take anything but more power points, though.