@roland we actually had a big discussion about this last week.
The promotion of the evaluation of some nodes on the vertex shader instead of the fragment shader is an optimization that is done under the hood. The idea here is that often times it is FAR more expensive to do operations per pixel vs. per vertex. In most cases this optimization has considerable benefits on performance of a scene.
However the user CAN overwrite this optimization by telling a node that it should be evaluated in a specific “TARGET” shader.
That said, NME users weren’t aware that the optimization was happening, SO we added this triangle as a means of flagging to the user which nodes are “eligible” for the optimization when the shader compiles.
All in all this is here to help ensure the smoothest most powerful scene possible, but without this triangle and the ability to let users know it’s happening, it is too hidden. That’s why we added it this week.