Does enabling snapshots change what data is stored as the permanent source of truth?

No. Enabling snapshots doesn't delete, replace, or modify any of the original events — the complete, permanent event history remains fully intact in the event store, exactly as it would without snapshotting. A snapshot is purely an additional, disposable optimization that sits alongside that history, used only to speed up aggregate loading. Every snapshot could be deleted at any time and the system would keep working correctly, just slower, falling back to replaying full event history on every load exactly as it did before snapshotting was configured. This matters because it means snapshotting is never a risky operation from a data-integrity standpoint — it's purely a performance optimization layered on top of a source of truth that never changes.