The main reason why binance became the third largest and third highest marketcap in the crypto space is because ethereum blockchain is having a big problem regarding the high transaction fee that makes plenty of project shifted to the much lesser and more convenient chain which is the binance smart chain.
Binance gets massive demand from ethereum users and i can say that 1 ethereum user will also use its own ethereum address to be connected with BSC chain. Ethereum's scalability has become the main problem and this forced so many parties are looking for alternative coin and binance is the best answer.
The ecosystem created by binance is very very big.