BNB is a good altcoin but have it in mind that no altcoin will ever be the next bitcoin, it's a fallacy. Bitcoin remains my number one holding occupying 50% of my portfolio. Binance has been good with developments and updates, hence BNB price keeps soaring. Also, people buy in BNB to take position on Binance IEO, hence price increases.
Binance is of course an altcoin that has good prospects, in addition to a strong platform with far reaching management, Binance is also owned by one of the largest crypto exchanges in the world. This reputation is a guarantee that Binance coins have a higher value in the future.
But to be as big as bitcoin is certainly not as easy as imagined because bitcoin is the "spirit" of cryptocurrency and without bitcoin cryptocurrency trading there would be no. If it's made without bitcoin, it's probably not popular now.