What do you think about holding BTC on Electrum Portable on pendrive?

Title says it all. I hold my BTC this way and feel pretty safe with it honestly. Electrum wallet is protected locally by password, and seed phrase is written on paper, stored safe on my boat.

Can you tell me main differences between this method and actual hardware wallets like Trezor? Considering that in the end you are storing just private keys, because actual coins are still on blockchain, regardless of method. Am I wrong somewhere? In which aspects these methods differ exactly?

Maybe its a noob question but theres some fear around this topic lately so I’d like to get opinions