> How much does it matter whether or not we can accurately observe, characterize, and validate the processes at work inside large reasoning models

If you don't or cannot, then it's the kind of sufficiently advanced technology that looks like magic. Except it is the problematic type of magic, like X-ray. They "magically" let you see the bones inside bodies. But you discover that you shouldn't do it too often only when the damage has already been done.