The first million bitcoins mined by Satoshi have their public keys revealed, million other coins are sitting in addresses with exposed public keys, but nobody is going to find them any time soon, this puzzle is the proof of that, when we can't even find a key with 32 first 0s easily, how can one finds a key with 64 unknown hex characters?
It's best not to use an address with exposed public key for long term cold storage. That's it, like when they say lock the doors before going to bed, not neccesarily a bad thing to do, after all there is no central bank to hold and keep bitcoins safe, you alone are responsible to keep them safe, now saying to not reuse addresses is a security advice, ignore it, nothing will happen, there is only a tiny percentage of probability of compromise.
Remember, before Satoshi launches bitcoin, he had asked several mathematicians and cryptography experts to test the security of public keys, they all gave thumbs up for launch.