For me the reason I’ve switched is Windows just feels bloated and slow to use especially on less powerful hardware. When I open a program on Linux it just opens instantly, no spinning wheel, no waiting 5 seconds for the start menu to finally decide to open
That and package management, on NixOS I have a list of installed programs and system config all in one place, so no random applications I installed 3 years ago and forgot about, uninstallers that don’t work, dodgey .exes etc