IT techs that use imaging/deployment and/or DHCP/PXE will often be working with a computer's GUID, UUID, or MAC address. For example, you have received a shipment of new desktops and are preloading your Windows Active Directory with the new computer names in the desired OU. You will then be ready to boot them and have the new computers network PXE and start installing your company base image. The packaging gives you the UUID but you need to provide the GUID to the computer proerties in AD.
Some tools to help convert back and forth between the different formats.
Example:
WFLGNVLAB01
UUID: 457A9480-E7BE-11E2-9C6A-8851FB69DFA3
GUID: 80947A45-BEE7-E211-9C6A-8851FB69DFA3