why the capitalisation dipped by 2 times compared to bnb? previously were the same
No, they were never the same, except for a few fleeting moments. BNB has clearly been ahead since mid February.
The answer to your question is simple: one is a pump n dump shitcoin led by an egomaniac and the other is Binance Coin.
What is a shitcoin ? Bitcoin is not pumped and dumped ? It's not just an unknow man ? All of the coin are shitcoin or all of the coin could be the same thing as a real money.
You could be a troll or not...
BNB is the same thing than all other coin... And BSV or BTC too !
BNB has a perfectly functionnal usecase.
Bitcoin does too: store of wealth and everyday payments with LN.
No need of a fork of a fork of Bitcoin.