Point of GtkDrawingArea?

[Chris Seaton <chris chrisseaton com>]

What's the point of GtkDrawingArea? I want to write my own widget, and 
the docs say that's what GtkDrawingArea is for, but what does 
subclassing it add over just subclassing GtkWidget?

I looked at the source code in gtkdrawingarea.c and there's less than a 
screen of code! What's the point of this class? Is subclassing it the 
correct thing to do when writing your own widget?

Thanks

Chris Seaton