According to the disposition of the sender, the term mail art is accented either on the word "mail" or the word "art".
So some mailart is more of a letter, and some mailart is more an intentional esthetic object. Or mailart is still mail, and mail is still art. Or whenever we mail art, it is correspondence. Or some days, mail; some days, art. Or artists can't avoid mail, and correspondents can't avoid art. Or mailart is a hybrid of a hybrid, sometimes taking the form of a letter, sometimes taking esthetic form.
To extend the discussion, Roy decorates the obverse of the card with a fluxist axiom by Ben Vautier ("art does not exist"), and he adds the word "FINE" in a clear Arenellian hand. (I once spent the night at the Ruth and Marvin Sackner Archive of Concrete and Visual Poetry, and in my quarters rested a large contraption filled with fluxist pieces by Vautier, most decorated with Vautier's handwriting--so I recognized his hand immediately. Also, it's hard to avoid knowledge of Vautier if you live in my realm.)
Roy Arenella and Ben Vautier, "FINE art does not exist" (20 Mar 2001)
Many of Vautier's pieces actually revolve around aphoristic evaluations of art. But he turns a spotlight on other areas of knowledge as well, as with the following found on his website:
Ben Vautier, "rien n'existe pas" (1991)
Here he tells us "nothing doesn't exist," a sentence that takes a bit of mind-twisting to force it show us all its meanings.
un violon d'ingres