No, the (implicit) point in the start of the thread is that multiple other encrypted mediums don't leak as much. Use them instead.
If you care enough to use encrypted email, you should probably seriously consider abandoning email. (signing is different - that's proof of identity and non-modification, useful in many non-private scenarios)
The point is, some is better than none. More is better than some.
So many people here pointing out holes that make it worse than a theoretically perfect system even though it's leagues ahead of where we are now.