apushatayid – If it is a Mitzvah for women (even if they are Eino Metzuva V’Oseh), then by definition learning can not be “nothing” (as otherwise it would violate Schar V’Onesh).
Not necessarily. The Rambam seems to disapprove of women learning in most situations. It is easily possible that if Hashem does not want you to do a mitzva and you do it anyway, that there is no schar.