The absolute fastest way to refill any coolant system is to pull a vacuum and refill. However, very few of us have the equipment to do that.
On my 2V SOHC, I will disconnect the heater line or the upper radiator hose. The reason this is done is to allow the coolant to enter the engine and displace the max amount of air. This reduces the number of heat/cool cycles are needed for the air to fully migrate to the degass bottle.
There are some engine designs that will almost never purge all of the air unless something else is done. The DOHC and 3.8 V6 come to mind. Which is why each engine came from the factory with a means to purge/check air from the crossover.
It is important to remember that some of the procedures used are for dealer techs. The average customer is expecting to drive the car away without any issues. Can you image telling a customer to watch the temperature guage and if it starts to over heat, pull over and let it cool? The cooling creates the partial vacuum needed to aid in air migration.
The other problems dealers have is with the high cost of labor. It is time consuming to allow a car to fully heat up (needed to make t-stat open), and full cool down (needed to create partial vacuum).
The tricks I have been taught to use after a coolant refill is to run the heater for that 1st test drive. If the heat output stops, there are steam bubbles in the line. Pull over. Over heating is happening.
The other tick I have been taught is to watch the temperature guage. If it is abnormally slow to warm up, that means air is trapped right around the t-stat/cross over. Pull over.