Optimistic verification borrows from optimistic rollups in that transactions are assumed to be honest by default with a network of off-chain actors responsible for submitting fraud proofs during the course of an optimistic window to disallow any fraudulent transactions. This mechanism adds a significant layer of security to the network, making it far more costly for a bad actor to conduct an attack versus the existing M of N mechanism. Externally verified networks rely on an honest majority assumption whereas optimistic verification relies on a single honest verifier assumption. Optimistic verification just needs one honest guard to behave honestly for the system to remain secure. Rather than a bad actor needing to co-opt M number of validators, that actor would need to co-opt all N actors, and the cost to attack the network becomes unbounded as the number of N fraud watchers increases. Naturally, the added security requires a trade-off - here, latency.