Very few human practices in software engineering have been proven to any level of rigor. But still, you have to make choices. There is usually no neutral position. You have to pick a particular language, a particular platform, a particular process, a particular team.
For me, the theory's pretty clear. The hard part about software is not the typing; it's the thinking. It's my experience that thought monocultures are less effective, so I always hire for diversity along many axes. I like having somebody with ops experience. Somebody else who loves the details of front-end work. Somebody else who has wrestled with deep optimizations. Young and old, functional and OO, careful and bold, etc, etc. I take as much variety as I can get, because the more diversity you have, the more problems you can spot and solve quickly.
An especially hard part about software is thinking about users. Good developers are always imagining the effect their choices have on the people they serve. But our imagination is limited by our experiences. Our empathy comes most easily for people like the ones we know. The more diverse your team, the more likely you are to spot and solve human problems.
So sure, it's not scientifically proven to be optimum. But the default isn't either. If we only question the things that seem novel, that's just a fancy way of arguing for a sort of generic orthodoxy.