Yields can also be a little more intangible
For instance, Shade or Beauty.
Both are yields of a system or component
Shade is an environmental service and it can reduce the surface temperature by up to 25 degrees celsius in hot climates.
Beauty is the aesthetic service that is no doubt valuable.
Think of how many people go places just for beauty.
A country drive, a beach, a waterfall.
When people are drawn they bring resources with them and more chance of positive interactions.
If you had a country roadside stall on the way to a famous picnic spot you'd do much better than a backroad
There are many more yields than the material. What others can you think of ?