There's a bit of overlap in practice though - and people are interested. Some are interested enough to make things like https://www.cadsketcher.com/ https://blender-archipack.org/ and others.

Those really blur the lines.

I'm not mixing up anything. I did not say or imply that Blender was a CAD tool. And yes, Blender is perfectly capable of creating precision models meant for physical printing. Is a good CAD app probably better at it? Sure. Has nothing to do with whether Blender can do it too in different ways.