1 billion times this. all your stuff lives on the blockchain and nothing actually resides on the cold storage device. the cold storage device is just a locked door in front of a wallet address (or addresses for multiple blockchains ETH/BTC/etc...). Even if a thief took your cold storage device, they really could not do anything without the seed phrase.
- there is a worst case scenario where say you left your ledger, a laptop where ledger was installed, the password to the laptop, the passcode to the ledger, the password to your software wallet (metamask) all in the same place. The thief would then not need the seed phrase and could just use the laptop by logging in to everything. installing the ledger to a new computer requires the seedphrase.
Yeah, it is waaay more important to never put your seed phrase anywhere digitally. don't store on your computer (even encrypting the text file), don't take a picture of the seed phrase on your phone. No one will ever need your seed phrase to help you with any issue concerning your wallet. phishing/social engineering seems like it is the #1 way people get their digital assets taken. never accept 'help' from anyone offering use remote access to your computer especially after posting about a crypto or wallet issue. don't approve smart contracts from websites you don't know and read what you are approving before clicking.