Crypto is all about the private key. Where is it? Who has access to it? Smart people hold their private key oﬄine, it’s COLD. When they plug it into the internet, it becomes HOT again. You’ve got a hot wallet.
Cold storage is complicated. Ultimately, it’s only a tactic, and a tactic without a strategy is prone for failure. Even COLD wallets may be HOT if they have been tampered with, meaning the moment you plug it into the internet your currency is stolen.