Regular folks that need MS Office cause it won’t run it properly and if you’ve to collaborate with others Open/Libre/OnlyOffice won’t cut it;
Regular folks that just installed a password manager (KeePassXC) and a browser (Firefox/Ungoogled) via flatpak only to find out that the KeePassXC app can’t communicate with the browser extension because people are “beating around the bush” on GitHub instead of fixing the issue;
Regular folks who want a simple Virtual Machine and have to go thought cumbersome installation procedures like this one just to reach the end and have error messages saying virtualization isn’t enable when, in fact, it is… or trying to use GNOME Boxes and have a sub-par virtualization experience;
Designers because Adobe apps won’t run properly without having a dedicated GPU, passthrough and a some hacky way to get the image back into your main system that will cause noticeable delays;
Gamers because of the reasons above + as the OP said a 5-15% hit in performance;
People that run old software / games because not even those will run properly on Wine;
A lot of electrical engineers as typical toolsets ( Circuit Design Suite combines Multisim and Ultiboard), IDEs and whatnot are primarily designed for Windows. And again there are alternatives such as KiCad and EasyEDA for some jobs but they don’t work great if you’ve to collaborate with others users of Multisim;
Labs that require data acquisition from specialized hardware because companies making that hardware won’t make drivers and software for Linux;
Architects because AutoCAD isn’t available (not even the limited web version works) and Libre/FreeCAD don’t cut it if you’ve to collaborate with AutoCAD users;
Developers, because if you aren’t a dip shit so up your ass that you only know how to use Docker and Github actions to deploy to some proprietary cloud solution you won’t even be able to find a decently working FTP/SFTP/FTPS desktop client (similar WinSCP or Cyberduck). There a few, all worse than the other and they all fail even at basic stuff like dragging and dropping a file.
Linux desktop is great, I love it but I don’t sugar coat it nor I’m delusional like most people I see here.
If you live in a bubble where you don’t have to collaborate with anyone else and you can use native Linux apps things might work, you might have a decent workflow and get stuff done but once you’ve to collaborate with other who use Windows/Mac it’s game over.
When you get/install Windows you pay a minimal license and get things working out of the box without further issues. Getting software to run is easy all vendors support whatever you’re trying to do and you get very high productivity from day zero. There are annoyances from time to time, sure, but they’re way fewer and simpler to deal with than the hoops you’ve to go through to get a minimal and viable/productive desktop experience on Linux. And I’m even talking about all the situations where you’ve to collaborate with others and the “alternatives” aren’t just up to it.
It all comes down to a question of how much time (days?) you want spend fixing shit in one platform that will be working out of the box in another one for a minimal fee. If you buy a Windows license and spend the time you would’ve spent dealing with Linux compatibility issues doing your actual job you’ll, most likely, get a better ROI.