Speaking for myself, I do it for compartmentalization, organization, and less distractions. If I need to pay bills or check personal emails, I’ll boot up my Linux installation. If I’m playing games or creating video content, I’ll boot up my Windows installation on an external SSD.
Plus, I use VMs on Linux to keep different aspects of my life separated, but organized. I have VMs for Banking, School, Work, Shopping, and Entertainment. I just don’t like the idea of doing everything on a single system, without some degree of separation.
Sometimes it more about staying informed, and less about “enjoyment”. But I’ve already said my piece on that part, so you do you.