Your also not including the fact that at least for the trezor, it has an on board real random number generator chip. This ensures that the signatures do not expose your private keys. Most software uses a psudo random number generator, which has caused many people to lose coins and causes people to generate keys that sometimes already have crypto on it! To date no one has hacked the coins from a Trezor device when used properly. It offers more redundancy then a simple paper wallet as well, especially if you use a safe deposit box.