Abandoned checkout, on the right channel
Entry on the started-checkout event with no purchase. Wait four hours. Branch on channel preference — WhatsApp if they are opted in, otherwise email. Set the goal to purchase, so anyone who buys exits immediately and stops receiving the sequence.
Protect margin on people who would buy anyway
Build a segment of high conversion probability with no discount in the last 60 days, and use it as an exclusion on the promotion. The offer goes to the people who need it.
Win back before they are gone
Churn risk is high, previously high customer value, opted in to email. Not “everyone quiet for 30 days” — a model output with visible drivers, and a segment that keeps itself current.