Will a recommendation letter such as that written for John F. Nash be convincing? I noticed in the book "A Beautiful Mind", by Sylvia Nasar, that a recommendation letter, for PhD applications, written for John F. Nash runs as follows: This man is a genius.

Then, out of curiosity, I wonder that if such reference letters for PhD applications work in the present days?  

Image taken from the Graduate Alumni Records of Princeton University:
Even though the event that inspired this questions may or may not have actually happened, the question is still a valid one. 

I suspect it greatly depends on who wrote the recommendation. If the person writing that recommendation is a great authority in this field and is known for not giving praise easily, then such a recommendation letter might help. On the other hand, if I were to write such a letter...