As long as the PGP private key is kept in a safe place storing your private keys in the cloud (while PGP encrypted) should be safe. Although if you are going to be securing something with your PGP key then you might as well backup your private keys in the same place that you keep your PGP key (ideally on an offline computer). If you are going to need a backup of your private keys, then you would probably need a backup of your PGP key as well so securing it this way is somewhat of a catch 22 - although you could encrypt it with a passphraise, although this is less secure
In practice it makes a difference where you might store your PGP key vs. your wallet.dat because the PGP key is static but the wallet.dat keeps changing and backups need to be made periodically. For example, you can store a cold (unencrypted) copy of your PGP key in a safety deposit box and use a very strong passphrase to encrypt the active copy without having to worry too much about forgetting the passphrase because you could always run to the bank in the event that you do forget. However, it probably is not convenient to run to your safety deposit box every night with your updated wallet.dat each time your private keys change.
can you explain how a wallet.dat gets outdated? isn't it automatically checking the blockchain to display your final balance?
