Because having the bone hanging out the bottom would mean only about 50% of the used space would be used for the message, constraining it inside a funky shape would cut that down even further.
edited to add
(after seeing your sketch it's not taking up as much space as I envisioned)
I just tried to help but nope. I meant that the city scape would be in the wing shape and then the lettering overlapping.
Just cover it in ketchup.I'm sorry but I wouldn't eat at any restaurant that serves dog.