From what kind of sites? The kind that know and care about WebGPU support enough to include your iframe? That's some heavy selection bias if my assumption is true. Not a lot of low end smart phones visiting the kind of person that runs that kind of site.
That's what I figured. So that supports the idea that it's only measuring a very skewed set of visitors from Webgl, JS, and gfx designer type sites. I'd put the iframe on my very non-JS, non-webgl, non-gfx sites to skew the other way but I don't put JS scripts on sites.
