Without a real email address, you won't be able to access your account (if you didn't back up your recovery phrase)
So does this mean they store your seed too? Or they use a hash to protect it using the password?
Looks like it works similarly to blockchain.com where they store the encrypted wallet file in their servers so users are able to access their wallet with just an email and password using a browser in any device, while also giving them a discounted non-custodial experience. Discounted because of the unknown part of how those wallet files are being kept and that encrypted or not, it's a lot better to not have your keys lying around somewhere.
Who keeps the private keys?
When users register, they create a wallet client-side and then immediately encrypt the private key using a secret which never leaves their device. We safeguard their encrypted wallet, but they maintain absolute control over it. We designed the security architecture so that transactions can be signed in any modern browser, meaning users can enjoy a familiar and easy experience without the risk of any unauthorized activity.