If you use the seed, and it gets compromised, then you immediately lost all your coins. But if you only save the password safely, and backup the wallet file in several locations, then you gain a form of multi-factor authentication, because if the password gets compromised - the wallet file is still needed, and vice versa.
The seed may be useful for portability of the wallet, but it's a major security risk compared to just using the password and wallet file.
Am I missing something here?