The minimum NHRA standard for a race car leaves the cable from alternator to battery hot at all times. When you watch a car burn to the ground because that charge cable remained hot AFTER the cut off switch is thrown, changes your perspective on leaving hot wires anywhere in the car. Once thrown, nothing outside about a 2' cube is hot in any of my cars. That is a freshened up, cleaner version of my wiring schematic up I've used for 20+ years in race cars with a cut off switch.
To answer a different question of why the ford solenoid, I prefer that the starter load never see the cut off switch. Running the load through the cut off then to the ford relay, nope, not on my stuff.
You may create a loop if you aren't careful with feeding everything at the ford solenoid as your buspoint.
Depends on what you are doing and trying to accomplish.