The keys can be printed out on a paper. If you set a strong enough passphrase for the secret keys, you can upload them somewhere, too.
I should rarely use my special keys (or passphrases of the secret keys) so as to keep them safer. And simpler authentication is more efficient for normal web services. GPG authentication may not be fast enough.
I should rarely use my special keys (or passphrases of the secret keys) so as to keep them safer. And simpler authentication is more efficient for normal web services. GPG authentication may not be fast enough.