Just because some people can multiply large numbers in their head, that doesn't mean that other people won't benefit from a pocket calculator.

To be fair, a notebook and a pen are fantastic thinking tools. You maybe could argue that the tools provided here are not that useful but thinking tools in general are a necessity, Daniel Dennet makes some compeling arguments for this.

"You can't do much carpentry with your bare hands, and you can't do much thinking with your bare brain". — Bo Dahlbom

I think this speaks to the idea of rubber ducking.

I think a fair amount of problem solving ability is at the boundary of the internal and external.

Of course this is imprecise scientifically, but hopefully the idea is clear.