Has all that much to do with the value or lack of value of thinking inside or outside the box.
It has more to do with how the literal words, and living and acting on them, actually affect our behavioral outcomes. I think another thing businesses have tended to do is have retreats where leaders take employees through a bunch of things like rope climbing, or exercises where they have to trust their fellow employees. I have never been to one of those and don't know what the research shows on stuff like that.
But there is a kind of neurolinguistic programming aspect to this.
On the other hand, trying to think inside a cardboard box of that size would pretty much drive me bonkers. I don't think I would be much good at either inside or ouside the box thinking sitting in a box like that. The puzzle piece example was more interesting to me. But, essentially athletes see the value of cross training. We need to look to more of that in learning, workplace, etc. The effect of music in the classroom or at work is one good place to start research. It bothers me tremendously that the arts have been taken out of schools to save money. Who can stare at math problems and pages in books all day long?