I tend to agree with Hegel when it comes to art, to view art as something which is simply sensuous is an outdated notion. There are very few accomplished, modern artists who will create a piece of art simply to look nice.
As Hegel would say, art must point to something beyond itself. This is clearly a function, and to view it as anything else is to misinterpret it.
This is also very similar to Kant, because as Kant says, in our first moment we see something as being beautiful, once we are past this first moment it is no longer beautiful and it turns into something that we see as good. This seems true (at least from a personal stand point) because I rarely focus on art solely on its beauty, almost any philosopher would look past this and ask what is it trying to convey? All this to say that function is a key part of art, the function is to convey something beyond itself.