Advantage+ Shopping is excellent at harvesting existing demand efficiently. It is much weaker when your catalogue is small, your creative supply is thin or your budget cannot clear learning.
01
Where ASC wins
Broad catalogues, steady creative supply and enough daily budget to exit learning quickly. In those accounts ASC usually beats manually structured campaigns on both CPA and time spent managing them.
02
Where it struggles
Niche products, considered purchases with long cycles, and accounts where existing-customer budget caps are left at default so the campaign quietly retargets its way to a flattering ROAS.
03
Run it honestly
Set the existing-customer cap deliberately, compare against a manual campaign in a split test, and judge on incremental new-customer revenue.