[Shank]

> I think what matters is that you keep a TODO list in whatever format is useful to you.

It's just that. That's why programmers keep making todo lists. Because some people want more flexibility, some want less. Some need some specific feature set, and some think other features are stupid. They're simple enough systems that people can build whatever flavor they want -- and it'll work for them -- rather than be constrained to whatever is available.