As @SeanP said, geometry created in Dynamo are not actually built in Revit until you specifically do so using nodes. Yes, there is a preview of the geometry in Revit as a blue/purplish line but that is just a preview. It can be disabled under View -> Background 3D Preview -> Available Previews -> Revit Background Preview.
To make it into a model or detail line within Revit, use the node ModelCurve.ByCurve or DetailCurve.ByCurve respectively.