Bc we vastly reduce the search space to find the secret?

Brute-forcing a known key (ie, any UTXOs with non-zero balances) becomes way easier when I don't have guess the entire universe.

= low entropy, by chance, isn't necessarily bad... You could randomly draw a key in Earth...
except that an attacker is already trying that (on the chance it might not be chance, lol). So that screws you anyway.

What I hear Simplestacker saying is in "some hint"; that gives me somewhere to go, some place to start guessing, knowing that the spoils may lay here