YES ESPC uses more powder that a coolwhip container, but gives you so much better coating performance and is not bothered by the weather, humidity, position of your mouth, or the phase of the moon as is tumble coating. Powder is so inexpensive, I do not worry about any waste.
The gun technique gives me the ability to coat any metal object that will fit in my LARGE Oster oven. You cannot do that with a plastic whip cream container!
A have always stood my boolits up to bake even after shaking, so ESPC is no big whoop. You develop the hand motor skills to sit them up rather fast and accurately after a little practice. I can spray, bake, and re-fill trays at the same time, so it is just a little assembly line.