Ismael Celis's current thinking: once you model around commands and events, the scope of true errors shrinks dramatically. A failed payment isn't an error — it's something that happens in the domain and should be recorded as a PaymentFailed event, opening doors for domain-level reactions (offer a different payment form, grant a discount). True exceptions are reserved for technical/network issues; the Sourced dashboard visualises running reactors, retries with configurable exponential backoff, and eventually de-registers a reactor when retries are exhausted so you can fix and replay.