Just resurrecting this zombie as there was a really interesting study which proposes that an advanced civilisation might want to live in what it calls a “red frame environment”: an area with heavy time dilation which would therefore allow it to explore outwards in a way that synchronises the rate of passing time. They could position objects in and out of different reference frames to exploit time dilation to build resources or advance their technology very quickly. And it gives them time to advance compared to anybody outside the red frame and especially compared to an attacking fleet of ships flying towards them through interstellar space. A very interesting study indeed.