I am sure that BNB will be more in demand in the future than ETH. First of all, there are huge transfer fees. Secondly, the speed of the transaction is not encouraging. Because of this, all new projects are made on the basis of BCS
Many projects are currently being launched on BSC network for high transaction fee and low transaction speed of Ethereum network. We are also using BSC network ourselves. But ethereum developers are trying to solve this problem. You notice that ETH's transaction fee has started to decrease. And if this problem is fully solved, ETH network will become popular again. So I don't think there will be more demand for BNB than ETH in the future.