Currently, a lot of people are moving to the BSC and buying BNB, because of that, the BNB prices has pumped from $45 at the beginning of February to $120 in only few days. Also, BSC supports other coins like BTC or DOT, giving alternative uses to coin hodlers.
Also, Binance Bridge is a useful tool to change between networks quickly, easy and inexpensive. BNB is used to trade, pay fees, or invest in DeFi applications.
Besides the BinanceSmartChain factor. The success of Defi on this basis has made the price of Bnb have increased recently like a successful Pancake. but I saw yesterday besides that there were also IEOs that had to hold BNB so that many people bought BNB. whenever there is an IEO in binance the average gives high returns. most recently the SFP has increased 30X the sales price