Isn’t this just a case of different tools for different jobs (or the right tool for the right job)? Rst clearly has some advantages for this use case but, at least for me, markdown is much faster and clearer to understand when jotting down my daily notes.
Absolutely. I prefer rst for the use case of writing a technical book, because of the specific benefits I get from its additional complexity. My blog is still in markdown.
Having done a little of both, I find RST is faster just because I can lookup whatever syntax I need to keep going while with markdown I often stop to scream because I can't make it do what I want. Either is easy enough to understand when reading raw text - this is mostly about good style though, RST gives you more options for bad style that is hard to read.