Programming is not the backbone of primary education and you shouldn't design a education curriculum around a niche subject. Primary education is for teaching literacy, history, and arithmetic not a trade.

But you can certainly teach programming with pencil and paper. Some of the most influential programmers in history of computer science did not do their work on physical computers or used (now) esoteric methods like punch-cards as input. Several of my university CS classes were all pencil and paper, especially midterms and exams.

On laptops?

You do know they have the ability to keep notes, right?

How long does it take to draw diagrams and modify and annotate them over time on note taking apps? You can do it in seconds by hand. The situation applies to drawing arrows between phrases and such too. For some things, the simple way is the best.

It's not one or the other, even in the classroom. Computers didn't kill handwriting or print, and latter don't hinder the use of computers. They all complement each other.

Useless tangent: In my experience (= K-12 + 10 years at universities) the best way to lock things in ones head is to take quick handwritten notes and then reread, correct, and enter them as notes on one's computer.

I didn't make myself clear. I agree, I use pen and paper every day to complement my laptop use, and it's miles better for some things than can be accomplished digitally even today.

It's still doable to only have a laptop and use that for everything, if not practical or quick enough in many cases. Pen and paper is nice to have, but it's not 100% required.