the seed created by Electrum has 128 bits of entropy which is as safe as private keys.
This also puts up a red flag, 128 bits of entropy. Why not just say 128 random bits or 128 bits of info. Why create another term.
It also seems it might be possible to create a database of seeds. If computing power increases and users increases. You might get a match. Always wary of when passwords are shortened.
128 bits/ 8 bits per byte is 16 bytes of information.