Obviously that's their prerogative and they can do whatever they want but objectively speaking it is more work and I sincerely hope the trend will die.
Writing a blog post would require you to do the same, but not share while you are going through the experience (so no helpful replies from your followers etc), then having to edit (as blog def requires something a bit more polished) and post it on the blog that you need to run or have run for you some way. And then you would need to somehow get people to actually read that still.
So I totally believe them (besides believing them they are telling me their valid view in the first place).
That being said, if using twitter is easier for them and it's a choice of either publishing this stuff on Twitter or not at all, then I'm glad they use Twitter.
Edit: I just noticed that the blog posts were originally published as twitter threads, so maybe my point doesn't stand.