Smart Bidding is guessing
Low conversion volume gives automated strategies nothing to learn from. Manual control and longer evaluation windows are correct here, not old-fashioned.
Attribution windows that are too short lie
If the decision takes three weeks and the window is seven days, the campaigns that started the sale get no credit and you will cut them.
Landed cost is the real cost
Freight and returns on bulky goods can exceed the ad cost entirely. Break-even has to include both or the whole model is fiction.
More: the furniture vertical.