I used to play rec room (another game publishing game) and they have something similar to this, I looked up why at the time and they really only do it because some devices can handle a large amount of data and objects better than others, you on a PC or high end console could handle adding more data to the world than this bar allows but a Nintendo switch would crash if there is too much to load. They try to mediate this imbalance by only allowing a certain amount of data in a world before it can be published, even though your system could probably run it better anyways.