How so? Proof of location and date of birth is all that's needed.
Actually it's not.. maybe. There are varying definitions of Natural born citizen. Some require knowledge of the citizenship of the parent(s). That's not on the Certification, nor on the Certificate, although the place of birth of the Parents is.
The Certification is enough to prove citizenship, but not necessarily natural born citizenship.
Oh and there is another requirement which no birth document can prove, the requirement to have been 14 years a resident in the United States.