Why build megastructures? Just move planets around to make habitable worlds

In 1960, Freeman Dyson proposed how advanced civilizations could create megastructures that enclosed their system, allowing them to harness all of their star's energy and multiplying the habitable space they could occupy. In 2015, the astronomical community was intrigued when the star KIC 8462852 (aka Tabby's Star) began to dim inexplicably. While an analysis of the star's light curve in 2018 revealed that the dimming pattern was more characteristic of dust than a solid structure, Tabby's Star focused attention on the concept of megastructures and their associated technosignatures.