Nice chart plotting the tradeoff between security and convenience. One addition I'd add is paper wallets, which are generally far more inconvenient than the options listed. And while paper wallets can be a secure method for longterm storage they have severe security drawbacks:

• generating the private key must be done on an uncompromised device, which is often difficult to determine.
• paper wallets are subject to loss and potentially theft, especially if unencrypted (see BIP38).