What are ZK Rollups and why do people care about them?

ZK Rollups are a Layer 2 scaling solution that processes transactions off the main blockchain and then proves their validity on chain using cryptography. People care because ZK Rollups significantly reduce fees while keeping security at the same level as the main network.
ZK Rollups rely on zero knowledge proofs to confirm that every transaction is valid before it is finalized. This means the blockchain does not need to recheck all data, only the proof, which keeps the system fast and secure.
Many developers prefer ZK Rollups because they offer faster finality and stronger security guarantees compared to some alternatives. Funds remain protected by the main chain, even if the off chain system fails.