A passphrase also protects against someone acquiring your private key by some other means. For example, if you accidentally copy the key file somewhere, or some tool (Dropbox, OwnCloud, any cloud syncing tool) syncs it to an unsecured or compromised location. The passphrase adds a knowledge factor to the key's security.
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A passphrase also protects against someone acquiring your private key by some other means. For example, if you accidentally copy the key file somewhere, or some tool (Dropbox, OwnCloud, any cloud syncing tool) syncs it to an unsecured or compromised location. The passphrase adds a knowledge factor to the key's security.