I think it is nice when there is a well thought out spec for something. But in this particular case, I think it is not compatible enough with other tools.

In particular, Markdown has a todos (using the same `[ ]`) and just uses indentation for grouping. I find this more intuitive and it renders in markdown renderers.

For priorities, I have adopted the notation of OneNote which puts exclamation and Unicode star symbol next to the todo brackets.

I also use some other conventions:

[-] for obsolete rather than [~].

[>] for postponed until later

Implemented in my Todo manager TUI: https://github.com/coezbek/rodo