Why put every one in one group?

Hi SI team & fellow S.I.ers

This is perhaps a somewhat philosophical question but…
Why would I want to put every one in a group in my case a user group in one group!

http://finalbug.net/

What are the advantages.
I am wondering if it is a way to tie everything up?!?
Or like putting a roof on a house!?!

e.g. in my case could I do the following:

a) Put every one in a group
b) Have profiles searchable but not viewable
c) Other advantages?!?!?!?!

Would be curious if some one has something to say about this!

thanks

Paul