I've read through that (hard to read, because of the bad formatting) but I still don't understand why you would do that instead of Playwright, Puppeteer etc. - The only reason seems to be "This technique certainly has its limits.".
Solutions that want to automate in the context of their customers' browser. For example, ListPerfectly, a solution for cross-listing to eBay, Poshmark, etc, does this in their browser extension.
>bad formatting
If you can elaborate, I would very much appreciate it. I'm always interested in doing better.
Why use Puppeteer etc. when you don't have to? What is the argument for using these additional tools versus not using them?