[CentOS] CentOS 6 yum Groupinstall vs Manual install

Gentlemen,

I have a question regarding yum groupinstall vs just using yum install. 
I have been reading tutorials online (for example how to run a Centos 
LAMP). Most of the tutorials have examples to install httpd, mysql, etc 
using yum install httpd....

The reason for this e-mail is that I noticed in yum grouplist that there 
is an option to install Web Server, MySQL database server, etc.

Question: Is there any advantage to using yum groupinstall for a 
webserver as opposed to using yum install httpd? I am just curious why 
most online docs dont mention groupinstall and only reference installing 
each app manually one by one.

Any information would be appreciated