You probably don’t think your work is valuable but someone is waiting for your unique perspective. It doesn’t need to be perfect; nothing is.
You can also write publicly but for your future self, which drops the barrier to entry.
Of course you’re allowed not to write or not to share. It’s not for everyone. But don’t let fear or self-doubt stand in your way either.
People put a lot of effort in stuff they do in the hope that somebody will find it useful, will give them some praise, and maybe even some money. That stuff doesn't tend to happen if you don't talk about your stuff. Build it and they'll come usually doesn't work.
I presume the author doesn't fall for any of these and is happy. But for many it would be a dark pattern to follow.
I come from a long line of tinkerers that have sat in damp sheds playing with junk. Testing themselves, their tools and often others patience. There is an inherent beauty and calmness to this. This has value and shouldn't be dismissed.