But it's a resource for web devs, mostly used by web devs. Reinforced by the web.dev domain name, which surprised me. I've never seen .dev domain before.

All audit tools make recommendations that many of us will ignore. I have zero intention of using webp images for example.

I don't think your claim that "nightmares" will happen is warranted. Shiny new site audit tools are fun. Enjoy it, there's no nightmare!