I was about to say no, but realize that I did write that incorrectly. To re-write, it would have redundantly said:

trying to strengthen the strong points is generally accomplished via a method that further increases susceptibility to human error (you have to implement "hand-done" encryption), whereas the encryption (the existing strong point) was fine as it was.

Does that help? I did have it wrong, thinking that implementing some form of hand-done encryption was an attempt to strengthen the weak points... but such activity would actually be in the "already-strong" category.