I think it is very rude to compare BNB and ETH. ETH is a huge ecosystem that brought a lot in the world of cryptocurrency, and BNB is just a coin on the exchange
Just because of BNB is an exchange coin doesn't mean it can be compared with ETH. Realistically, BNB is trying to build its own ecosystem by launching Binance chain. Binance DEX is helping accelerate this. As of now, if ETH is technique based then BNB is economics based. If it's simply marketcap compare, I dare say one day BNB would surpass ETH.