I don't think the issue is performance though. The unspoken part of this comparison is in bold:
"Linux vs Windows tested in 10 games. In the games we could find that work on linux, the performance was 17% faster on average. In all the rest of the games, Windows worked 100% better."
Aside from performance, I also noticed that older PC games work better on Linux than Windows nowadays. I really enjoy playing games from the late 90's to early 2000's, and they tend to run great on Linux with proton. Just the last year I've played all of Baldurs Gate 1, Icewind Dale 1 and Icewind Dale 2 on my scrappy Lenovo laptop and it's been great.
With proton the benefit can be +/- by quite a large margin to the point where I wouldn't rely on this data to say that Linux is faster by default. Though it's promising that Linux CAN compete with windows in performance despite the added layer of abstraction necessary to run many titles.