Agreed.

The upside is that it does not leave the most important aspect open to interpretation.

But it prevents this from being text-only at the point of creation:

You'll most likely need some programmatic environment to create non-trivial diagrams.

But then the question is: Why not just an SVG instead?

It strikes me as odd that boxes are placed precisely using pixels, but the size of text is not specified, as far as I can tell. So you use real pixels to specify boxes, but still can't render a canvas exactly/consistently?

I’m playing with 3d positions derived from higher dimensions, right now.