What is the importance of deploying digital certificates on application servers in the domain ?

From: Marlon Brown (marlon_brown_at_hotmail.com)
Date: 10/29/04 

Date: Fri, 29 Oct 2004 11:41:24 -0700

Win2000SP4 AD domain.

Application server admin requests that I install digital certificates in the
domain to make all Application servers more protected when being accessed
from the internal network.

I would like to double check and see implications and level of importance of
doing that ? Please advise if that is troublesome to implement.