I have test to tell whether art is great, sort of like your sofa test.
In 1000 years, when archaeologists dig it up, will they know it was great art?
test = a test
I live a short ways from a town in south central indiana that has lots of artists and thus lots of galleries. I've bought (probably) twenty or thirty paintings. A couple are phenomonally beautiful. (stare at them and get lost for a few hours type beauty) others are merely pretty. But all were worth the money. That is great art