I think the goal is stability, which is key for coral growth and vitality. Constantly adding additives gets tiresome and expensive. Once you have a tank that can suck up 20ppm of calcium a day you'll understand better. Most people don't have the need for constant addition of Ca and Alk and do well with a simple two part additive method or just frequent water changes.
Now buying additives in bulk and using an automatic dosing system is to me the best method, but this is fairly new technology for us
