The pretty obvious reason in my opinion: Ethereum's fees have been quite high for a while, and Binance Smart Chain(BSC)'s fees are drastically lower. And yes, BSC is like magnitudes more centralized than Ethereum, but it comes to show how a lot of people don't care that much if a certain project is decentralization or not as long as they can make their bets on certain tokens.
It's true. If decentralized platform can't solve that main problem (gas fees) on cryptoverse, people don't care anymore if it centralized or not as long as it gives more benefit using them. Bsc gives solution while ethereum still on the old track (high fees). That's why the price keep mooning. But I don't know, with this hype I still think the current price of bnb is overpriced. Imho