i own both NGM and NGM petite.  all of them do sag the breasts, and in ways that are only appropriate when there's absolutely no support.  the more "realistic" shape is accurate but only when the "Gravity" in the title is appropriate.  for instance, both of those pictures show way too much space between the breasts if someone is wearing a bra rather than just a strappy thing with no support.  and that line underneath is completely unrealistic given something that's cut like the  outfit in question with a bra underneath.  for most outfits in Poserdom, the morphs might be appropriate.  certainly, the bulk of nudes can be improved with them.  but those are not realistic clothed shapes, unless the clothes don't provide support.

as Conniekat8 has said, people want what they want, realism be damned, so it's cool.  please enjoy and have fun, if she includes them.  but they are not in the least more realistic in this situation, though they are when used as in the promotional images.