I would say it increases the surface area that _must be attacked_ rather than the surface area available for a single attack. So like, if you have a square they just have to attack the square but if you have a cube they have to attack six squares. And really the attack vector of primary concern, in my opinion, is the creation of the key and that math can be verified separately. Once the multisig wallet is made, the hardware doesn't matter that much going forward if you're not using the set up forfrequent spending. just a quick thought
Discussion
Sure multisig helps the security of the setup immensely. Especially when distributed by multiple, geographically diverse holders.
Whether single-sig or multisig, the goal of the hardware wallet is to protect private keys. I was wondering if a smaller HW wallet(s) total software code and silicon metal base has merits with "putting eggs in one vendor basket."
We also have BIP-39/44 24-word seed phrases.
I've always considered the HW wallet's highest purpose to securely create private keys which should really be, as you point out, stored as seed words in physical medium. For me, cold storage is HWW agnostic ultimately.
Yeah, this.
Steel washers remain undefeated.
I can see having a HWW if its a "warm" wallet and you sometimes need to sign a tx.
But nothing comes out of my cold storage so I just have a watch only wallet and the seed on steel.
That’s my thinking. Properly generate good entropy keys and keep them analogue securely forever.