Nice, good to know about that. I'd consider it if I did use Joplin for projects that lend itself to a board task management structure, although for larger work projects I actually use Asana.
For my personal/smaller/GTD weekly task lists that I use Joplin for, I ended up using CSS (along with Rich Markdown, and Folding in Code Mirror Editor) to work out a system that is useful for me: CSS to hide completed checkbox items in the Editor (specifically using Rich Markdown) - #4 by semyl - mainly I use the "z" option to make the completed items very small and grey.
I did also apply a bunch of CSS to the Outline plugin:
And then I move the "This is the day" and "Tomorrow, tomorrow" markers (headings) along each day, so any tasks nested in the days within "Days done, gone the sun" are collapsed at the top.
It's a little "manual" if I need to move tasks down to another day, but it is working pretty well for me (and is what I want, with a single note per week rather than multiple notes).