As far as how Bitcoin Core leaves the addresses visible, I have mentioned how this is a mistake before. I remember someone making an argument about this which was not convincing at all. If someone finds the wallet.dat file for some reason, and the see the funds
If someone gets their hands on your wallet, your security has already failed.
But ultimately you always want to store your wallets encrypted with an encryption software on top of it.
If that makes you feel better, nobody is stopping you

On a technical level, I don't even think it would be possible for Bitcoin Core to run without knowing your wallet addresses. With each new block, it updates your wallet based on all new transactions on the blockchain. If it wouldn't know your addresses, it would have to "rewind" all blocks when you unlock your wallet. That's going to take a while, and could even make pruning impossible if you barely open your wallet.