It’s just sugar with a teensy bit of the natural brown color from unrefined molasses left in it. I don’t find your observation that it takes 5 or 10 times as much of it to sweeten something to be true for me whatsoever, it’s almost exactly the same, and leaves me wondering if perhaps you also find that today’s low-flow toilets need to be flushed dozens of times to work, or that you turn on modern showers and just a tiny trickle comes out :)
They aren’t “airtight”, that would awful. They are well-insulated and designed to take advantage of passive solar heating and air exchange cooling. The way roofs and windows and orientation on the land is usually done for western homes is just terribly inefficient for capturing and releasing heat in the right ways. Just some thick walls, a bank of windows facing the sunrise ,and some proper roof vents that can be opened when it’s hot is all most passive houses really are.
It’s pretty hard to imagine a way for groups of people with varying goals and interests to operate without some form of value exchange. This can either be barter, or some form of currency. Our specific kind of extractive capitalism based on creating endless cycles of debt and credit can certainly be replaced with any number of alternatives, but the idea of money itself is just too basic and useful to humans, imo.