In order for groups to function, the people that make them up have to operate in a sufficiently shared reality. The best one of those to operate in is, of course, actual reality. The more you deviate from that, the less cohesive your organization is.
We don’t operate in actual reality though. We operate in perceived reality and there’s no way to escape that. But to your main point, I agree that if we all operate within the same perceived reality then the group will be more cohesive.