No, it makes sense for any person with any skill set. Just because you are a developer doesn't mean you want to setup everything yourself. We use plenty of tools to make our own experience better and more focused, based on what we want to do.
If I'm a programmer, and I want to publish blog posts, sometimes I don't want to care about the setup that makes me able to publish blog posts, I just want to post something.
> why Substack doesn’t get with the program and just support MathJax and colored syntax highlighting already
This, I don't know. Should have been done ages ago.
1. Make my blog using mkdocs material plus GitHub pages so it has all the nice code and math rendering features (plus things like admonitions and all the other nice things in mkdocs material).
2. On each post have a Substack signup button.
3. When I make a new post I want to send to subscribers, I manually create a short text-only teaser post on Substack (paragraph or two), with a link to my main blog that says “read more here”.
I know this doesn’t auto-push new posts to subscribers but I am ok with that given that I won’t be writing more than once a week at most.