For example: Your character want to find on own land plot the fridge. Or want to find TV on current premises to watch and get some fun, or news. Hence item search need be fast, so doesn't need to iterate over thousands of objects, to find right one. Objects (balls) can also be removed, or move between plots (yellow), premises (red), rooms(blue). Typically when editing world. But maybe I can figure out interesting use case, for more than that?
Fun side, I have used physics to test performance and dynamics, of objects changing, adding and removing to regions. So far so good.
However, this is isolated experiment. And need be tested together with other mechanics. Also adding Lua into loop, may affect final optimisation results.
Whether I will keep physics or not, is yet to be seen. All depending on performance. I will say chances are slim atm. But who knows.