Every Rollup should ultimately use ZK, but to varying degrees. For example, after transitioning to L2 OP Stack, Celo adopted Succinct's OP Succinct Lite, which is very suitable for Rollup within the current OP architecture. The most intuitive improvement is that it can reduce the challenge period to less than 7 days, as low as 24 hours. Its principle is to only use ZK during disputes, rather than turning the entire Rollup into a ZK Rollup. Its advantage is that it reduces the waiting time for withdrawal, and the project party does not need to change the existing architecture. At the same time, there is no need to continuously pay ZK verification costs. Only a ZK proof needs to be generated in case of dispute, and verification can be completed once. Therefore, it retains the low-cost characteristics of Optimal Rollup while achieving dispute resolution efficiency similar to ZK Rollup. But OP Succinct Lite is still applied to Optimistic models and needs to retain the challenge window, so it cannot minimize the challenge period to the extreme. Traditional Optimistic Rollup typically requires a 7-day challenge period, with a 'dispute game' where any potential challenger is given sufficient time to check their status and initiate a dispute. This is a multi round fight process, with multiple round trips between the proposer and challenger, and each round requiring L1 submission, making it a slow and complex 'multi round fight'. The design of OP Succinct Lite is that after a dispute occurs, the proposer only needs to generate one ZK proof at a time, and the smart contract can be verified and arbitrated in one go, without waiting for multiple rounds of fighting or L1 confirmation, greatly reducing the complexity of the entire process. And this time cannot be shortened to the level of a complete ZK Rollup because it needs to meet at least two time windows: challenge time and proof time, mainly in the proof time. Although zkVM such as SP1 is fast, proving a state transition function still takes several tens of minutes to several hours, and submitting a challenge also requires sufficient time. Therefore, 1 day is currently the shortest finality configuration supported by the official. From a long-term trend perspective, ZK is an ultimate solution that is based on consensus, as the Optimistic model cannot prove all information at once. Its working mode gradually checks and replays transactions in L1 in case of disputes. Its finality essentially depends on the challenge period setting and must exist. Therefore, it can never achieve the immediacy of pure ZK. The pursuit of fast and efficient finality ultimately leads to the ZK solution. However, at present, the vast majority of mainstream Rollups (such as Arbitrarum, Base, etc.) have adopted Optimal architecture, which started early and has already occupied market share, making migration difficult. Therefore, OP Succinct Lite and other solutions provide an intermediate form of ZK capability that can be obtained without reconstruction, avoiding the dilemma of having to choose between ZK and OP.