Why IGraphElementWithData?

Hello.

I'm trying to write custom nodes for visual scripting and I noticed that existing nodes do not store their data in member variables. Instead they implement IGraphElementWithData and access their data using flow.stack.GetElementData(). Why is that?

Is there a problem with storing data in member variables like this?

Code (CSharp):

1. public class MyNode : Unit
2. {
3.   private int mMyData;
4. }

I need my custom node to keep a reference to a C# script that is on the same GameObject than the script machine. I tried that:

Code (CSharp):

1. public class MyNode : Unit, IGraphEventListener
2. {
3.   private MyScript mMyScript;
4.  
5.   public void StartListening(GraphStack stack)
6.   {
7.     mMyScript = stack.gameObject.GetComponent<MyScript>();
8.   }
9. }

It seams to work. Is there a problem with this approach? Should I use IGraphElementWithData to keep the reference to my script instead?

Thanks.