In this video (@6:40), Clint from Clint's Reptiles says basically the same thing that you do above. On the other hand, I believe snakes instinctually seek freedom. In the wild, if a snake gets stuck in a 4x2x2 space, it won't live very long because no 4x2x2 space in the wild is going to meet a snake's needs for very long. So, in addition to its basic physical needs, I think it's important to provide your snake with a sense of freedom. That's why open my snake's enclosure and give him the opportunity to roam almost every day.
I don’t disagree with the sentiment. I would absolutely love to see mine move freely. I do disagree though that a snake seeks freedom. Ball pythons especially. I’d argue they seek security above all else.