The interaction between L2 and between L2 and L1 is essentially cross trust domain. Because the state is isolated, communication relies on asynchronous messages (bridges, inboxes/out boxes), and requires proof generation, submission, verification, and then L1 finality, it is difficult to achieve true "synchronous composability" (a transaction safely moves both L1 and L2 states simultaneously). If Native Rollup takes back the verification authority from L1 in the future, it will bring two direct changes: Firstly, the boundary of trust has been narrowed. L2 is no longer an external system that requires separate verification, but has become an execution result personally checked by L1. When all verifications are completed uniformly by L1, the state of L2 is no longer as "foreign" in L1's eyes, and the trust cost of cross domain calls decreases. Secondly, it is easier to stack with the Based Sequencer to achieve tighter combinations. The meaning of 'Based Sequencer' is that the transaction sorting of L2 is entrusted to the proposer/builder of L1. Once the sorting is also driven by L1 and the validation is native to L1, L2 becomes closer to the "extended execution layer of L1" from an "independently operated chain". Under this overlay model, a transaction has the opportunity to safely touch both L1 and L2 states within the same L1 block time window; External domains/sequencers can more directly utilize the liquidity and status of L1; The dependency on the asynchronous bridge logic of 'send message first → wait for proof → execute' will be significantly reduced.