Very cool. Is that wallet.dat encrypted itself? Is it possible to password protect the client to prevent theft to someone who has access to my computer? Ubuntu user here.
When you first create your Electrum wallet it gives you your seed (to be able to restore it in the future) and ask you to encrypt your wallet. Just use a strong password and your seed, that is inside your electrum.dat file will be encrypted (public addresses are not encrypted, but they are already public anyways). You'll be asked to enter your password in order to spend your coins.
Your seed is your access to all your private keys. You must not lose it.