A ZK rollup posts validity proofs so the L1 can verify correctness without re-executing every transaction.
ZK systems can offer faster finality to L1 than optimistic challenge windows, with heavier proving costs.
In research workflows, ZK rollup is usually interpreted with Layer 2, Starknet, Validity proof, and Rollup rather than as a standalone signal. Throughput, finality, and fee markets determine user experience and where activity migrates during congestion.