I think that telling people people that they can achieve _arbitrary_ things through enough effort is just wrong: it sets up unrealistic expectations and makes them blame themselves when things don't work out, because they must not have tried enough. Telling someone who's 5 feet tall as an adult and not particularly athletic that if they just work hard enough they can become a successful Olympic swimmer is not OK.
It's a tough communication problem, because "maybe you can reach this goal if you work really hard and happen to be lucky too" is a much harder concept to communicate and internalize than "you can reach this goal if you just work hard". It's also a tough problem in trying to figure out what expectations ought to be "realistic" for a given child, because of all the biases we bring to such evaluations. So erring somewhat on the side of emphasizing growth mindset can make sense, and should absolutely be done when doing evaluation, but you have to be pretty careful how you communicate the resulting recommendations.
Past that, the unfortunate thing is that Dweck's disciples (and I use the word specifically for its religious connotations) go overboard on the "everything is possible with a growth mindset" thing, in exactly the way that I think is harmful. I see this in a lot of elementary school teachers; they love this book, but end up in the "growth mindset solves everything" trap, at least in their communication.
I should note that unlike many things in that field Dweck's work actually replicates in large pre-registered studies, albeit ones still done by Dweck herself. The effects are quite small on average, but maybe on the margin (i.e. for students who are more likely to doubt themselves for various reasons) might be significant.
That said, I would be happier if someone who is not Dweck were able to reproduce her results, and I have ~0 confidence that "growth mindset as practiced in elementary schools today" is at all useful...