What is Arbitrum?Arbitrum is a technology suite designed to scale Ethereum. You can use Arbitrum chains to do all things you do on Ethereum — use Web3 apps, deploy smart contracts, etc., but your transactions will be cheaper and faster.
Why use Arbitrum?1. Trustless security.2. Compatibility with Ethereum.3. Scalability.4. Minimum cost.
Trustless security: Security rooted in Ethereum, with any one party able to ensure correct Layer 2 result
Compatibility with Ethereum: Able to run unmodified EVM contracts and unmodified Ethereum transaction
Scalability: Moving contracts’ computation and storage off of the main Ethereum chain, allowing much higher throughput
Minimum cost: Designed and engineered to minimize the L1 gas footprint of the system, minimizing per-transaction cost.
Why do I need ETH to use the Arbitrum network?When moving funds (ETH and non-ETH) from Ethereum (L1) to Arbitrum (L2), you'll need to have ETH in your wallet on the corresponding Arbitrum chain.