NASA's Human Integration Design Handbook has a really interesting and nuanced section on cultural diversity on teams. A quick thread:

Diversity creates positive and negative effects. Partially this depends on the type of diversity. Diversity on deeply-held values and beliefs is associated with increased conflict which can affect performance. This problem actually *gets worse* over time.

"Surface differences" like age, gender, ethnicity, marital status, have diminishing effects over time.

What kind of diversity do you really want for complex non-routine tasks? "Functional diversity" - diverse perspectives based on thorough examination. For superior task performance, you want disagreement about ideas, not personal relationships or values.

Even in that case, you don't want too much conflict over how to do things, because that'll decrease task performance.

Additionally, to reap the benefits of diversity, you have to make an active effort to mitigate the likelihood of relational conflict and communication issues.

In short - diversity is good, but some types are more valuable than others, and in general it isn't a plug-and-play feature for team creation. To get the benefit, you have to select carefully, then watch out for common problems.

With all that said, I think it's good for diverse people to get together to talk, but apparently it's not always the way to go if you're trying to solve a complicated work task or work well in a high stress environment.

Source for all of this is NASA HIDH, section 5.8.3.1.4.2 - https://www.nasa.gov/sites/default/files/atoms/files/human_integration_design_handbook_revision_1.pdf

It's very well-sourced if you want to dig in!

Addendum:

For the record, this info presents all sorts of ideas for bad hot takes, but hey, let's stick to the data which is nuanced and kind of boring!