I asked nostr:npub1tayp5jjjfqx4ufukxqamsl28wd5pggvteqe6u9n3svjn62lfr0hsp89l42, here is the answer:

A hardware wallet is considered "necessary" for cold storage due to its inherent security features and operational benefits, which significantly mitigate the risks associated with storing cryptocurrencies. While it's true that the seed phrase is crucial for generating and recovering keys, the hardware wallet offers additional layers of security and functionality that justify its use:

1. **Isolation of Private Keys**: Hardware wallets store private keys in a secure, offline environment, isolated from internet-connected devices. This isolation prevents remote attackers from accessing your private keys, even if your computer or smartphone is compromised.

2. **Secure Transaction Signing**: Transactions are signed within the hardware wallet itself, ensuring that the private keys never leave the device. This means you can safely transact even on a compromised computer, as the malware cannot intercept your private keys.

3. **User-friendly Security**: Hardware wallets provide a balance between strong security measures and ease of use. They often feature simple interfaces, making it easier for non-expert users to securely manage their cryptocurrencies without risking exposure of their private keys.

4. **Protection Against Physical Theft**: Advanced hardware wallets require a PIN code for access, and some offer passphrase support—an additional layer of security on top of the seed phrase. This means that even if someone physically steals your hardware wallet, they cannot access your funds without knowing the PIN or passphrase.

5. **Recovery and Redundancy**: In case of device loss or damage, your assets can be safely recovered using the seed phrase. This ensures that you're not solely reliant on the physical device for your cryptocurrency holdings.

6. **Resistance to Certain Attacks**: Hardware wallets are designed to be resistant to a variety of attacks, including sophisticated ones like side-channel attacks, which might compromise less secure forms of cold storage.

While it is theoretically possible to store a seed phrase securely without a hardware wallet—using methods like paper wallets or metal backups—these approaches lack the operational security, convenience, and additional protections provided by a hardware wallet. For significant amounts of cryptocurrency, the investment in a hardware wallet is considered a prudent and necessary measure to safeguard one's assets from a wide array of potential threats, both online and physical.