Thanks! Including some kind of ability to default to exclude AI results, or even to start with results under a listed category, be it "Short Videos", Web", or anything else, would seem to be an obvious quality-of-life or ease-of-use features on Google, but it's been many years since Google last made even some meager attempt to not "be evil" to its users. These days, no one should be the least bit surprised to see Google hoovering up every last bit of private data on users it can, the users' intentions and best interests be damned.
It's not clear to me what sort of added utility AI is supposed to add to users' experience, and with or without AI, Google search results have consistently and substantially declined in quality over the past few years, so users must be satisfied to take their meager wins where they can find them.
TLDR: this add-on effectively provides a very simple and straightforward way to default to results that don't include AI replies. It looks like not everyone who's tried it has had a similar experience, but speaking for myself, it works exactly as I had hoped it would, and I am grateful that some kind soul went out of his or her way to take the time to provide this service.