Well, it is a major part of the movie, so it's a bit of a surprising question. TBH. But it was dolls that showed women doing all sorts of jobs, often powerful or traditionally male jobs, and often ones that girls wouldn't see women doing in real life (which is still true, to some extent). And Barbie had her own home and car (not as big a deal now but it was when it started) and had a boyfriend, not a husband, and no kids.
TBH it's a shame there aren't more similar dolls aimed at boys, rather than mostly being military or superheroes. Boys like pretend play too, and representation also matters for them. Maybe they do exist and I'm just not aware of them though. I mean there are different Kens, but not nearly as many.
Don't think you need me to tell you about the other side (unrealistic body types - and encouragement of plastic over-consumption, though that second one is not exactly confined to Barbie). Mattel did start making genuine efforts at changing the representation way back in the 80s, which is why the movie can have Barbies in Barbie-land who look like pretty much anyone, but the "stereotypical Barbie" is still a thing, of course.
Some people kinda just don't value creative play and letting kids play with dolls, and wouldn't let their kids play with Barbies of any body shape, because they should be playing with Lego instead.
Though actually that was one of the features of the movie that I really disliked - the girls smashing up their baby dolls. They still have their place too, and it's not great making it seem as if independent women should never want to play-act at being mothers as well as being Presidents or lawyers. There was a strong mother-daughter relationship, of course, but that first baby-doll smashing scene didn't sit right with me at all.