It was launched in September 2019 by Binance exchange in conjunction with Paxos Trust Company and approved by New York Department of Financial services. It is stablecoins backed by US dollars on ratio 1:1. The BUSD is similar to BTCB which is a stablecoin but pegged to bitcoin and BGBP also a stable coin pegged to British pound, all on Binance chain.
It is traded on Binance exchange and many notable exchanges. According to Binance exchange Paxos acts as custodian as well as issuer for Binance USD, it also has the function of regularly audit the dollar holdings.
As a stablecoin against us dollar it help to stabilize crypto market, because anyone holding will have rest of mind that the price can not go down, because it is a stablecoin of an exchange it help Binance to customize this product for its users.