You can go through 10 tutorials and think you "got" something, until you need to articulate it and you realize maybe you missed some step. Of course I'm generalizing, but I also find this process helps "stick" things into my mind. I might completely forget something 1 week from now if I don't put it into writing.
I also find a huge waste keeping things on my computer, so I publish them. I started doing this on my blog https://flaviocopes.com with the things I knew already, and of which I had already lots of notes spread around, and then when I got "tired" of this I turned this into learning new things as well. I mix and match these approaches.
Sometimes I go into "series" of posts to dive into a tech for many days in a row.
I might search something on Google and spend 1 hour looking for the correct answer on SO or other blogs, and when I finally get the "canonical" one buried somewhere, or some different but valid solutions, I write a blog post to make it my canonical in the future (I find I very often reference my posts and update them as I go).
Writing down things as a learning process is worth it even if you just target yourself. I don't write to teach anyone. I write to learn, then if the result is good I think it's a disservice not to share the work with others.
Then I agree that crappy tutorials are not worth sharing most of the times. If you target beginners it's cool to write basic stuff, but it should be a nicely crafted content rather than rushing things and copy/pasting examples taken from somewhere else.