When you set a password electrum encrypts the seed using that password. So there is no need to use another encryption app.
No offense intended, but that's a matter of opinion.
Electrum has never used key stretching, which makes wallet files with shorter/weaker passwords in the realm of being brute-forcible. For example, an Electrum wallet with a password containing 8 lowercase letters or digits would cost somewhere around $100-$200 to brute-force (some back-of-the-napkin calculations can be found here).
Personally I'd avoid uploading my wallet to the cloud unless I was certain it had a strong password, or used an additional layer of encryption with strong key stretching such as Veracrypt as shorena mentioned.
