BNB VS Eth - Invest in ETH since BNB is centralized
Eth is soon launching its version 2.0 but the fact is that that many blockchains are based in ETH, ETH is open source and less centralized despite the fact that binance has a working product (its centralized exchange) and its lending and dex platform. While the deFi will make the ETH bigger as you need ETH to lend the deFi tokens. So it is time to make your investment in ETH instead of buying BNB tokens which may fail anytime.
Both are different blockchains with many projects based on them, but more are based on Ethereum, also both have their different ideas which keeps making them valuable. Just like you indicated, Defi is making Ethereum big in the same way, Binance exchange etc, is making BNB big as well, therefore just like you need Ethereum to access many services, Invest in some projects on the Ethereum blockchain, in the same way, you will need BNB to access services on the Binance platform; so it means that, both have things which will keep making them valuable. I agree that BNB is centralized, but looking at the success so far from the Binance team shows that they are experts who are doing everything they can to ensure the continuous growth of their platform, hence BNB is not other altcoins which can fail anytime. Lastly, investing in both of them, to me, can also be a good idea.