There are quite a lot of ads, but

It's nice that you can keep getting hidden quest rewards of 200 gems by watching ads. Since ads play automatically when you just leave the game on for time quests, you don't need to be actively playing the game. Ads do pop up frequently during gameplay, but if you go back to the Playo home screen and press play again, the ads disappear. After repeating this, I managed to complete the quest by clearing the 40 ads and merging two watermelons, which would fill up, by watching the pinwheel ads frequently and removing them.