Okay so here is my true opinion.
Flourishing is it just showing off? I have yet to see anybody do cardistry that wasn’t showing off. Like Zack stated in his discussion with his friend Stamp collectors show off to other stamp collectors, flourishers make movies to show off to other flourishers. Do I think flourishing was made for showing off? Yes I do. Furthering I do not consider this necessarily a bad thing.
Do I think that the majority of the flourishing videos art? *shakes the magic eight ball* Sources say no. I am sure it is art to other flourishers but to the outside observer it looks like showing off.
However if the flourishers actually took the time and plan the video completely through ie blocking body movements, creating a choreographed routine then yes I think the video may have a chance at being artsy.
If you had absolutely no music for a flourishing video is there still a way to convey emotion? Yes, body language, facial expression. Interpret dance is an example I am going to use. The dancer is dancing without music but is still conveying emotion through movements of his/her body. I am pretty sure if flourishers spend endless hours perfecting very technical multiple packet cuts, they will not have any problem with learning basic body movements to help convey something to the audience.
Lets come to grips here Cardistry without magic is a form of juggling, I accept juggling as an art form because the majority of jugglers out there make it an art form with the exception Cardists.
Intermission
http://www.youtube.com/watch?v=ykQjrqEO_dU
http://www.youtube.com/watch?v=9Bax63oYrn0
Videos linked just for fun.
Switching a little now
I completely agree that we are entertainers and performers. I really do not consider much of modern magic an art. Especially this new stealth snake style of magic, walking up to someone performing an effect and moving on, you want anything to be art it has to involve art to begin with.
Cardistry/magic=Performance art? Possibly, magic/cardistry can really only be considered performance art if the theatrics are focused on more then the effect itself. When I say theatrics I do not mean glitz and glamor like lights fancy music and etc. I mean theatrics by your performance character, personality, speech, blocking, audience interaction, and most of all Subtext what your character is feeling internally.
Now with that said my conclusion is this, Cardisty, Magic, Card Cheating, Gambling is not art. Art is Performance, Painting, Sculpting, etc.