Binance is reliable and trust worthy platform that's why they made their child coin so much useful that people can use it in many ways. And that's why BNB much popular child coin than other exchange child coins. Binance is top ranked exchange and IEO platform. If you see past results then almost every ieo projects succeed whom use Binance IEO platform. And for joying their ieo event you need to hold BNB. And as you mentioned of course you can earn some passive income also. Most people do that which is great deal too.