Yes, it is recommended to maintain a small balance of ETH on Arbitrum One for smooth and uninterrupted L2 transaction operations, including retrying failed transactions, confirming transactions, and redeeming L2 tokens. While it is not necessary to have ETH on Arbitrum for using transfer tools or transferring GRT to Arbitrum, having a small amount of ETH (around $1-5) for gas fees after transferring GRT is recommended to facilitate seamless transactions.

it is necessary to hold a small amount of ETH on Arbitrum One prior to initiating a Layer 2 (L2) transfer from the Ethereum mainnet to Arbitrum. This ETH is required to pay for transaction fees when you perform actions on the Arbitrum network, such as transferring assets or interacting with smart contracts. When you bridge assets from Ethereum to Arbitrum, you typically pay the gas fees in ETH, and having it in your Arbitrum wallet ensures that you can facilitate transactions smoothly after the transfer.