I can say this as someone with ADHD, neurodiversity specifically allows me to approach problems in radically different manners than my coworkers which sometimes makes things an absolute cake walk for me and sometimes makes them nearly insurmountable. This is a result of my approach to problem solving which has been trained on the problems I've experienced in the past and my natural disposition. I think an entirely homogeneous company would have issues with tunnel vision - they might be excellent at dealing with some issues and absolutely flabbergasted with others... having a more diverse team ensures that you've got more varied experiences to draw on when approaching problems.

Aside from all that, I think that diversity makes teams more healthy to work within - if everyone looks the same (straight white male) you're likely going to have cliquish social assumptions form in your team that will prevent you from hiring an excellent candidate that doesn't happen to fit the mold and might force out people who aren't what they appear: trans men, gay men and asians that appear white. As a company it's important to keep your workplace friendly to all potential employees and having a homogeneous company makes it more likely that a closed off social culture will form that makes life difficult for new employees.

I have never seen any studies to support this but thought I'd add at least a well reasoned opinion.