it turns out that tasks that seem easy to us can in fact require such a specialized region

The causation is reversed here - I'm sure you know this but I think it's worth pointing out explicitly.

It's because we have a specialized region for some tasks, that they seem to easy to us. (Things seem hard when we need to concentrate on them, and when we don't know how to do them.) And we have a specialized region for these tasks because they need it: we can't do them well using our "general-purpose thinking" even if we do concentrate. (People with Broca's or Vernicke's aphasia can't compensate well using conscious thought.)