The OS should be able to natively open plaintext. The joy of markdown is it still largely works in plaintext.
Except it doesn't because it isn't, the challenges above are from editing raw. There is no joy in reading/editing anything non-primitive in MD
You will not get any joy reading/editing non-primitive things in a markdown language not designed for reading/editing non-primitive things.
You will get joy from using the right tool for the right task.
which a plaint text editor is decidedly not since it fails at the most basic editing tasks - search and search&replace. That is the joy killer. Thus the tool described in the blog is closer to the right one for this task
Markdown was designed for plaintext editors. Plaintext editors are - by the definition of markdown - a right tool for the job of markdown.
I don't have anything else to add here.