So let me ask you if you partch IIS do you have to reboot the box?
If there is an SQL server or FTP relay on that box will you not have to shut down and dependant servers or services on other boxes relating to that box?
If you have a process box that shares drive space will you not have to stop those processes?
A reboot of a server requires far more planning than restarting a service! on all but linux kernal patches you do not have to reboot the system, infact you can install servers (mail, db, ftp, ...) and not reboot the system.
A reboot from an administrative stand point is an huge pain in the rear end, thats not even taking into account the increased risk of disc failure or other hardware issues that a reboot entails.
Your obviously not a Systems Engineer, and your IT experience is limited so just take my word on this one..