So, would a display be called cardistry?
Most displays, like D&D's Werm, would be considered cardistry, yes. Let me try to clarify:
If it's not magic, it's probably cardistry.
If you think it's a flourish, it probably fits under cardistry.
Think of it this way... if it aims to show something "out of this world" happened where the mechanics are hidden and it's by an apparent mysterious force or time continuum parallel dimension oddity, it's not cardistry. If it's an apparent feet of physical skill of dexterity, it's probably cardistry.
You can also add "magical flourishes" to your cardistry -- like for instance a production here and there to accent your cardistry routine. It's sort of like when you add a fancy fan to your magical routine, but the other way around: you're focusing on cardistry, not magic.
Hope that makes sense.