Security Audits provide check points for the security Auditors and inspectors to evaluate what is being protected against the resources ( Man, Money and Materials ) being spent to secure them. It also helps to identify loop-holes and lapses in systems which may not have been taken care of or were not anticipated during application deployment.
As Security Threat landscape evolves fast, Security Audits go beyond just developing a master or generic template to attending to companies issues as it pertains to the organizational attack surface.
Thanks