I'm talking about measuring toe directly, because that's how I do it. And it's actually how toe is defined.
A modern alignment rack does the toe measurement from the spindle/hub, because it does all of its measuring from the hub. But you hit it, that's a computerized system and it's programmed with the equations to come up with those numbers.
I'm well aware of how to measure toe "the old way", that's how I do it. The better tool doesn't use chalk either, it scribes a line on the tire tread.
Toe is defined as the difference of those measurements between the tires. How the modern alignment equipment does it is a computer short cut, it's easy to program the computer to measure the toe from the hub/spindle, and doing it that way you don't need a tech to set up a different measurement or more equipment. You just do it all from the single attachment point. It's not necessarily the better way to do it, it's just the faster/easier way if you have a computer doing the math and an unskilled tech setting up the equipment.
The contact patch is the only thing that matters. Maximizing the area of the contact patch under all of your different driving conditions is what should be determining what your alignment settings are, maximizing traction and even tire wear. Otherwise you're just looking at a bunch of numbers that don't mean anything.