No, I don't see people benchmarking BeOS on a Surface. Then again, I've never heard anybody say "well, if this whole Windows thing doesn't work out, I'll install Be on my Surface".
At any rate, this article isn't about the Steam Deck's performance, it's about Van Gogh specifically, and how it relates to other pieces of Zen 2 hardware. Testing with both Linux and Windows is useful. There's a comment elsewhere in this discussion by a Valve engineer saying that one of the issues the author saw is due to an ACPI handling issue in Linux. That's the sort of thing you catch by testing with multiple OSes.
At any rate, this article isn't about the Steam Deck's performance, it's about Van Gogh specifically, and how it relates to other pieces of Zen 2 hardware. Testing with both Linux and Windows is useful. There's a comment elsewhere in this discussion by a Valve engineer saying that one of the issues the author saw is due to an ACPI handling issue in Linux. That's the sort of thing you catch by testing with multiple OSes.