Here's a summary of Binance Coin (BNB) in 250 characters:

"Binance Coin (BNB) is the native cryptocurrency of the Binance exchange platform, launched in 2017 by Changpeng Zhao. BNB fuels transactions, listings, and partner rewards on Binance. It also powers the Binance Smart Chain, enabling decentralized applications and DeFi services. BNB's value is tied to the success of the Binance ecosystem."