Agreed. I'm currently working on a book on statistics[1] and keep discovering slight (and not so slight) misconceptions in my thinking thanks to the "optional" code examples and demonstrations. In the end, it seems the code examples won't be optional at all, but essential for understanding.

It's the same with many science and tech subjects. You don't really know it until you can code it. I'm intentionally converting some of the derivations/experiments into exercises for readers to complete on their own, so they can also benefit from this learning process.

[1] https://nobsstats.com/

I fully agree with you, but as a warning: most people are lazy, so if valuable points are hidden in exercises for the reader, there is a significant chance that many will miss them

A software project is a voyage of discovery.

True.

Being a developer in addition to being a writer helped tremendously.

That way, I was able to really try out more than just basic stuff and then write about it.

That can work, but it depends on what you're writing about. Different methods apply in different situations. But good writing has at the very least the advantage of doing what the article notes: it forces you to take what are vague convictions and impressions and justify them. You start to notice gaps in knowledge, inferential leaps, and logical inconsistencies. Only then, and only in empirical settings, do numbers come into play because they need to be motivated by and understood within some prior context. (Even when your writing begins with some number, that number is contextualized in your mind.) Of course, good writing presupposes humility and integrity or else you risk rationalizing and bullshitting.

Agreed, writing is necessary but not sufficient. But writing is still much better than nothing.

I gather that I am not adjacent to your field of practice by any means but this resonates with me deeply.

> As much as I enjoy writing to think, simply writing doesn't lead to reality testing

Yes it's possible to get cloistered. But I find writing and formulating ideas gives way to the ability to say it. What was ineffable becomes clear language I can test with people to see how it's received.