Google's AI is solid, but a lot of its benefit comes from the fact that it hasn't been enshittified into the ground like their search. The plain incontrovertible benefit is that it has the potential to reduce clicks from the user - instead of sending the UX through clicking into sites and then back to the main search pane the information is immediately available. That click through ends up being expensive for three main reasons 1 - the site is sometimes potato though google "solved" this with amp, 2 - it takes a while to scroll to the site entry passed all the sponsored links (a problem google created for themselves) and 3 - paywalls and "Please subscribe to our newsletter" popups are legion, but while this was always a little bit of a problem, it is a much more pronounced problem due to 1, the insertion of amp that threatens financial ruin on being crawled by google.

So, at the end of the day Google's AI is better than ye olde Google Search, and ye olde Google Search is now very difficult to accomplish because of how much Google has poisoned the well. Kagi is excellent but most normal people can't stomach paying for search when there's a "free" alternative so your options are Google's AI, Google's Search or and alternative search - most normal folks don't realize non-Google search alternatives exist (outside like Bing) so Google's AI ends up capturing a lot of usage.