Printing over HTTP must be prevented.
Some features may communicate with the vendor, sending system information or downloading data or components for the feature. Turning off this capability will prevent potentially sensitive information from being sent outside the enterprise and uncontrolled updates to the system. This setting prevents the client computer from printing over HTTP, which allows the computer to print to printers on the intranet as well as the internet.
How this relates to the STIG checklist: STIG vs SCAP benchmark.