It's also a part of any possible performance. If I remember correctly, Damien Hirst bought one of his own works back for a huge amount of money. It's considered as a performance.
'Subjectiveness' is an important condition, but in this case most importantly, art is institutional. Exhibiting, curating, buying art works are closely related with this issue. Even 'teaching' it.
'Appreciation' is personal. Here the pont is 'Evaluation' of art. Which goes back to the subject and question of "What's the required set of conditions that would make a work, work of art?"