Host Tags can include items that might pertain to other systems. Take for example Labtech Software. They use a System ID as well as a location ID, that can be used to identify agent installers by, or if your integrating links you can use that for external management links that might include Remote Control etc.
Now to install the management tools I have to create packages that are specific to the location, download them and then upload into a snapin of Fog. That is unless I have a generic Agent installer that I can pass an argument to like setup.exe /AgentLocID=<FogHostTag>