Bidding
Smart Bidding
Google's machine-learning bid strategies that optimise per auction.
Smart Bidding includes Maximise Conversions, Target CPA, Maximise Conversion Value and Target ROAS.
It needs enough conversion volume to learn — roughly 30 conversions in 30 days per campaign as a rule of thumb.
MyAd flags campaigns that have switched strategy before accumulating enough signal, a common cause of performance swings.