It doesn't surprise me at all. That number would have been zero without emulation like wine/Proton though.
> Anyone I know who plays games and uses Linux Dual boots.
As for myself, I don't play a lot, but a Linux version (native or emulated) plays a big role in deciding which games to buy when I do. It's not due to 'Open Source' reasons though.
Dual boot is too much of a mess for me, I have a separate Windows laptop which I barely use otherwise (it does have a few Windows-only games), it's a bit of an hassle too. I don't feel like booting it and discovering it needs to install 10000 updates. I have already had to reinstall Windows 10 once so I can run a game (the game didn't support the old Windows 10 build, and the in-place upgrade crashed). It's much easier when I can just take a break and run a game on the same Linux system I use regularly.