Reduce the number of validating nodes

As mentioned above, Layer 2 can take advantage of the security and decentralization level of the underlying blockchain, which we will elaborate on below. But the core concept here is that Layer 2 must submit some kind of proof to the underlying blockchain that the state change it initiated was valid.

Therefore, rollups can reduce the number of validators responsible for executing transactions in the Layer 2 network. Validation nodes can be permissioned entities that typically have more powerful hardware to compute transactions faster and at lower cost. The reason why this is possible is that the verification nodes are not responsible for reaching consensus, the consensus is reached by the underlying blockchain, and the smart contracts on the underlying blockchain need to verify the proofs submitted by Layer 2.