Binance Smart Chain (BSC), launched in September 2020, is a blockchain platform designed for fast transactions and decentralized applications, distinguishing itself from Ethereum-based decentralized finance (DeFi) platforms by utilizing Binance's own mainnet. It features the native token BNB and has gained popularity due to lower transaction fees and a growing ecosystem of applications. The document also offers a guide on setting up a Binance wallet and using the Binance Smart Chain extension to facilitate cross-chain transactions.