So far Binance has been the most trusted and reliable exchange that has gained the action of the globe as a global leading cryptocurrency exchange it's natives currency BNB, the blockchain was deployed after a sudden increase on ethereum gas fee. Binance blockchain was deployed as an alternative means of ethereum to transact smaller amount with a lesser transaction fee of $0.009 and $0.33 respectively depending on the amount you are transacting. Currently lots of coin and project has integrated in their blockchain through the bridging process and lot of exchange has added their blockchain as means of withdrawing coin to reduce the gas fee. To me BNB was just as an alternative of ethereum.
There is no doubt that Binance is an alternative smart contract to Ethereum which has a high gas fee, because it is really cheap to transact using the BSC network. Coins from Binance will always be my favorite coins that I hold, because every time I face a 4 year cycle, during a bearish season I will buy BNB.
You are correct ethereum gas fee was extremely high it was a serious concerns to people who were transacting on ethereum token, especially while swapping tokens on decentralized exchange you spent close 100$ to swap some token and it was a concern to investor and those who were involving themselves with IDOs. Some of the investors weren't able to meet up with the fees while there plans is to invest with a smaller amounts lesser than the fee itself, at some point IEO was then introduced so people could start making deposit and buy coin directly from exchange and hold till trading starts but at some level most of the investors weren't comfortable with it since they are so much concerned about privacy.
Therefore at this point Binance Smartchain became more useful and lessened the hassle for people to trade and some of the project began to list on pancakeswap where the could now use less than 1$ to sell of their coin, and again, pancakewap now became a competitor to uniswap, since Uni was mainly for ethereum blockchain. As time goes we began to have more Decentralized exchange launching regularly.