I am just after my first experiments with the method. The bias is what worries me as well. The experience is good, almost ecstatic but that suggests a higher concentration of dopamine in the brain. A higher level of dopamine is known for easier pattern recognition. We start to recognize patterns where there are none, we are getting prone to all kinds of staff like astrology, chiromancy, (or growth mindset).
But maybe that's not so bad, it can produce a lot of trash and from time to time some genuine insight - in the end that's how science is working.
Actually, my comment was not about the growth mindset, but if you want to know the reason why I think it is at least over-hyped... In short, the researches are not consistent and most of the confirming ones were conducted by Dweck's team. See for example big study from 2019
https://www.niesr.ac.uk/sites/default/files/publications/Changing%20Mindsets_0.pdf
or metanalysis
https://www.researchgate.net/publication/323565554_To_What_Extent_and_Under_Which_Circumstances_Are_Growth_Mind-Sets_Important_to_Academic_Achievement_Two_Meta-Analyses
They find either no effects or the effects are rather weak.
If you add to it that the growth mindset fits very well with social expectations and political correctness some dose of skepticism seems to be natural.