BNB (Binance Coin) is a cryptocurrency created by the Binance exchange. It was launched in 2017 and, at its inception, was operating on the Ethereum blockchain. Binance Coin (BNB) no longer operates on the Ethereum blockchain. In April 2019, Binance launched its blockchain, Binance Chain. This was done to increase the efficiency and speed of transactions on the Binance platform.

With the launch of Binance Chain, Binance Coin underwent a token swap, where holders of the ERC-20 token could exchange them for the native Binance Chain version.

As a native token of the Binance Chain, BNB is used to pay for transaction fees on the blockchain, including trading fees on the Binance CEX and the Binance DEX, a decentralized exchange built on top of the Binance Chain. Binance DEX allows users to trade and transact without needing a centralized intermediary. 

When a user holds BNB in their account and uses it to pay for trading fees, they receive a discount on their fees. The discount rate decreases over time.

Another use of BNB is that it can be used to participate in token sales on the Binance Launchpad platform, which is the exchange's token launch platform. The platform helps new projects raise funds by selling their tokens.

BNB also provides access to various other benefits, such as premium customer service, exclusive events, and promotions, as well as a wide range of products and services offered by Binance and its partners.

Additionally, Binance Chain and Binance DEX provide various other features, including creating custom tokens, launching initial exchange offerings (IEOs), and new use cases like decentralized lending, borrowing, and liquidity provision.

Overall, Binance Coin (BNB) is the native cryptocurrency of the Binance ecosystem. It provides various benefits to users of the Binance platform, including discounted trading fees, access to exclusive events and promotions, participation in token sales on the Binance Launchpad, and enabling decentralized trading and other financial services with Binance DEX.