Playboy and Hefner are a study in strange paradoxes. On the one hand, they were harbingers of the sexual revolution, both a symptom of and a contributor to the greater sexual permissiveness that emerged in the later 20th century. This was good for women in many ways (and ultimately for LGBTQA people as well), as it opened people's minds about what constituted normal and healthy sexuality and set the stage for challenges to the double standard.
Changes in social mores also encouraged the development of more reliable and convenient contraception and influenced the availability of abortion, changed attitudes about premarital sex, about unwed motherhood (how often does the child of a single mother get called a nameless bastard anymore), and about divorce, and about living together before marriage--all of which have frankly revolutionized the lives of women in western (and many other) countries. Even women who hold to more conservative sexual values have a choice (at least for now), and people are less likely to be pariahs because of their sexual choices involving consenting adults and that don't actually harm anyone. It's far from perfect yet, but we've come a long way.
However, much of this sexual "freedom" is definitely centered on "freeing" women to be sex objects and sexual "playmates" in order to cater to the fantasies and fetishes of men. Playboy (and other magazines in that vein) definitely didn't help with this at all, and likely made it worse. Many men still believe that women only have the "right" to be sexual beings so long as it's on terms and under conditions that men are comfortable with. And the idea that women have not just a right, but an obligation, to be sexy, available, and pleasing to men at all times by meeting a very narrow set of beauty and behavioral standards is very harmful to the health and well being of women and girls.
