However, I have no idea how the Binance Chain (network) works. Is it POW or POS? Are there miners, or is it completely centralized? Who will secure the network from attacks, etc? In my mind, security is more important than speed or costs of transaction.
Yup, we have no idea. As far as I can tell, they've released virtually no details about how the chain is secured. If we're depending on Binance to secure the chain, that's a huge step down from Ethereum's mining security. I remember seeing that BNB is supposed to be somehow integrated, perhaps as native currency.
I love Changpeng Zhao's intensity and vision, but I've also always thought of him as a trading engine guru, not an economics guy. I wonder if they know what they're doing.