I always click on the ads because I like the rewards. I've gotten 18 diamonds at least 8 times by now, plus some useful things like a rainbow unicorn, orcs, mana, seeds, etc. Sure, some rewards are garbage, but enough aren't that it's worth it. They never auto play ... I click on the reel, get a popup, and I click out in 5 seconds (one was a 10 second window, but it did give me diamonds.)
The only serious objection I have is when I clicked on an ad for a Buddhist retreat and got the big flashy, annoying "YOUR COMPUTER IS COMPROMISED! CLICK HERE TO FIX!" Ugh. I could not click out of it and had to reload the game. Extremely annoying. But like I say, it's happened once. I started getting the ads before the FA started, so it's been a while. Inno needs to vet the ads and make sure we aren't clicking on viruses. They should be able to do that rather than say "hey, it's not our faults."
I have had a couple ads freeze and then I had to reload the game. Overall, though, I think it's a net positive for me. I'm on PC so many that helps.