baltwo -
Im not sure why you would bother answering someone without helpful information or just to make a snide comment. It does not help the community discussion process at all.
In answer to your question, your knowing "why" is irrelavent. Many users would have many different reasons why. In any case my reason why is this. I have multiple user accounts on one computer. For security only two of those accounts are administrators with full privileges. This is so kids and guests can not get into restricted files and can not alter the operating system in an undesirable way or by mistake. A computer can need to be reset for hundreds of reasons (it locks up, a program stops responding, a network issue etc), and a reboot is necessary. In this case a non-administrator can not reboot the computer if any other user is logged on. In some settings the owner may wish to have the computer locked down like that so important work can not be disturbed but in my case I do not want that function. I want all users to have the ability to do a soft reboot. Unfortunately with OS Lion, Apple has made it so other users must do a hard reset by holding the power button or unplugging the machine. This is much harder on the system than a soft reset and is undesirable but it is the only way with Lion for non-administrators.
Again, none of this matters as to the "why" to you or anyone wishing to respond to this question. In the future it would be nice if posters such as yourself with no relavent information and plenty of snide comments would just move on to other posts and realize that those types of comments are distructive to the community and not helpful in any way.