The idea is that with this Secure Enclave, hackers who somehow manage to unlock your iPhone, they won’t be able to access these sensitive information. Unfortunately, it seems that researchers have discovered an unpatchable exploit that would potentially allow them access to the Secure Enclave.
The bad news is that this seems to affect quite a number of Apple products dating back to the iPhone 5s, as well as Apple’s Mac computers that use the T1 or T2 chipset, and also devices like the Apple Watch, Apple TV, and HomePod. The good news is that Apple has since fixed this exploit with the A12 and A13 chipset, meaning that newer devices will not be affected.
Also, the other good news is that with these types of hacks, the attacker would need direct physical access to your device, which means that being hacked remotely using this exploit would not be possible, so for the most part, you should be safe.