yes, bnb is one good alt to buy and detained. I've followed AirDrop the previous time bnb coins ico I do not think this project will be successful as it is now binance is the best trade and exchange binance reliable. bnb coins will be more expensive and valuable in the future.
Saying BNB will be more expensive in future is not a surety, anything can happen. With the current development which is massive, we expect that of course but not certain. By the way Ethereum remains best altcoin, not BNB.
BNB is more famous for being a more stable altcoin, but for now altcoin is still dominated by ethereum because of its ranking. so I think that so far bnb can not be said to be the best altcoin, but for the future maybe if they can compete in the market