EIP-7702 summary:

- new transaction type
- allows an regular EOA account (one that you have on metamask, zerion or rainbow) to become a smart account for duration of this transaction
- during the transaction, the smart account can do gasless transactions (eg sponsored by the app), batch transactions (eg approve and sell token at once), or use other keys to sign the transaction (eg passkeys)
- play with a great demo here: https://www.ithaca.xyz/writings/exp-0001

how is it different from ERC-4337?
- allows you to use the same address instead of starting and migrating to new wallet
- can be easier implemented by existing wallets and apps
- can still fall back to a regular EOA transaction in case the third party sequencer is offline
- no implementation lock in, you can upgrade the smart accounts code over time
- 7702 "sequencer" combines the roles of 4337 bundler and paymaster

confirmed on ETH mainnet in early 2024 and probably will follow on rollups soon after