Obligatory reference to Emacs Org-Mode [1].
Author's approach is basically Org-Mode with fewer helpers.
Org-mode's power is that, at core, it's just a text file, with gradual augmentation.
Then again, Org-Mode is a tool you must install, accessible through a limited list of clients (Emacs originally, but also VSCode), and the power of OP's approach is that it requires no external tools.