The team of Binance have got great ideas and they are putting those ideas to work.
This is why I am not surprised to see BNB grow that much.
The Binance chain, might not yet be a threat to ethereum, but I see it making a lot of impacts, despite being centralized.
A lot of coins will be seen migrate to it, but it will not be able to accommodate all, which is where ethereum will continue to be relevant.
You forget that BNB is a coin of a single exchange. If the exchange Binance will be hacked,the coin will fall dramatically. ETH does not have such threats.