Interesting read and not my area of expertise, but it sounds like a bunch of hypotheticals built on top of other hypotheticals. And, of course, I didn't read the scientific paper behind it[0] so I'm sure some of my misgivings on this "research" are due to the filter it's been presented through but it felt like this whole "an advanced alien civilization uploaded itself into a computer in a post-biological move" technology would be a whole lot bigger of a problem to solve than the "cooling down a system to achieve system processing performance required".

I couldn't help but laugh, though, in that the first thing that came to mind was The Hitchhiker's Guide to the Galaxy reference to the inhabitants of the legendary planet of Magrethea who went into hibernation to wait out the galactic economic collapse. Maybe that's the real reason they're sleeping!

[0] Which means the "telephone game" of this author's interpretation of the paper in order to write a story that will generate clicks is at play here.