A location is the physical location of a position or an asset. It describes where the position or asset can be found. As such it is only relevant if it is not already obvious based on any of the other attributes of the position or asset. Meaning there is no need for a location if everyone can find it based on the code, description or any other attribute of the position or asset.
Note that this description does not include systems because systems represent a group of positions and assets and therefore likely represent multiple locations. However, if you need a Location for a system, feel free to associate it.