Offloading is normal and it has a cost
Before any argument about these tools, it is worth being clear that delegating thinking to external aids is ordinary, ancient, and mostly good.
Writing offloads memory. Calculators offload arithmetic. Navigation offloads spatial reasoning. Search offloads recall. Each transfer freed capacity for something else, and no serious person proposes reversing them.
What the research on cognitive offloading, studied by Evan Risko, Sam Gilbert and others, establishes is not that offloading is bad. It is that it has a predictable structure: when we offload a task, our internal capacity for that task develops less or degrades, and we become progressively more reliant on the external aid.
The well-known illustration is the Google effect, described by Betsy Sparrow, Jenny Liu and Daniel Wegner in Science in 2011: when people expect information to remain available, they remember the information less well and remember where to find it better. That is an efficient reallocation rather than a deficit, provided the external store remains available and accurate.
So the question about any offloading is not whether capacity moves outward. It is whether the thing being offloaded was load-bearing for something else you need.
Arithmetic is a good case for offloading, because the number-sense that matters for judgement is largely separable from the mechanics of long division, and calculators are correct.
The argument of this lesson is that composition, analysis and reasoning are a worse case, for a specific reason: they are not just outputs, they are the process by which understanding is formed and checked. Which means offloading them removes the thing that would have told you the output was wrong.

