Short answer: for a scheduled daily report email backend, use cron to start one coordinator, then put one durable, idempotent delivery job per subscriber behind it; direct sending is simpler only while rerunning the whole audience is an acceptable recovery plan. For an edtech shipment update, the dominant billable term is usually shaped by fan-out, not by the single 02:00 trigger. If a run has S eligible subscribers, the system attempts roughly S email deliveries, while scheduling happens...