When adding piping system to a Revit model, it is desirable to label piping systems with their system type so that you see text on the piping line. Some examples of this are HW for Hot Water, CW for Cold Water, and S for Sanitary Waste.
In AutoCAD, piping systems are typically shown by drawing a line with a specific line type that displays the desired text. This works fine since the lines themselves contain no data and are just symbolic. Revit does not allow line types with text in the line like is allowed in AutoCAD. However, Revit makes it super easy to label piping systems with the appropriate text. I believe that the net result is the same, if not better.