If one of your private keys were compromised, then whoever has that private key will be able to figure out the rest of your private keys. All they have to do is go a few billion keys +/- of the one they have and they can get all of the private keys that you will ever use.

BIP32 derivation is vastly superior. In order to figure out all of your private keys, an attacker would need to know the master private key and the derivation paths. This means that if one of your private keys were compromised, your whole wallet isn't compromised. It is far easier to protect one key than it is to protect billions of keys.