

It eliminates the need for a lot of back and forth communication if you need to calculate stuff in space. Maybe scanning satelite images for example. And it shaves off valuable seconds if you - say - want to launch something from orbit to Earth. Most air defense mechanisms are not all that effective against stuff that comes straight down at a high speed and the idea of orbital weapons has been circulating for a while now (if not realised without public knowledge).
I just keep a Windows partition on my PCs for those few occasions where I need it. Usually about a tenth of the drive. For most stuff you can mess around with a vm or wine too but this way is easier imo. And realistically Windows 10 will be fine to use for the forseeable future. It’s still possible to use XP securely even today.