For the same transfer, why save so much on Layer 2?
One detail: Rollups are currently the mainstream Layer 2 approach, and come in two types: Optimistic Rollups and ZK Rollups.
Layer 2 security relies heavily on Ethereum mainnet: data and proofs ultimately need to be posted to mainnet. This is the main difference between Layer 2 and sidechains.
Understanding this matters more than memorizing a bunch of terminology. Knowing the rules helps you make clearer decisions; it isn’t for predicting price movements.
$ARB and $OP are the governance tokens of Arbitrum and Optimism, respectively.