When you google search for something (like say a product or service that you want to purchase), you'll see a couple ads at the top of the results.

Pi-hole usually prevents most ads from even displaying, but those always show up. If the ad was useful and you want to click through, it will generally block the request. I think the click through sends you to doubleclick or something.

I've never disabled pi-hole in that situation, but there have been times when it was an annoyance because the ad was actually relevant.