The cold wallet is the new way of putting your money in a piggy bank. Our Steemit wallet is not a cold wallet if you secure your keys and passwords it will be as safe as a cold wallet. Cold storage is the only way to go as hardware wallets are apparently vulnerable to brute forcing. I may not know what that really means but I will not trust those wallets if that is the case.
If hardware wallets can be abused to the point of being exploited I will still go with memorization like the Mission Impossible, The Rogue Nation idea. The only to keep it safe is in your head. If may take all the discipline in the world to do that but if that is what it takes to satisfy your paranoia then so be it.