What is the point of the upgrade modules? I did some testing and all they do is increase power output. And in that case, why not just use more reactors? I initially thought that the increased output of an upgraded reactor kept the uranium consumption the same so these reactors are space inefficient, but have high per unit/fuel efficiency. However that is not the case.

The increased output increases the uranium consumption too. So again, what is the point of using the upgrade modules over more reactors and taking up less/the same amount of space?