Wisher, I agree, the drainage isn't necessary, but the perforated pipes would allow more oxygen into the bottom of the pile.
I don't have issues with clay or sand in our yard, the soil itself is pretty nice. But we've got loads of rocks in there. Not anything big, mostly between a golf ball and tennis ball in size, but you can't drive a shovel in more than 2-3 inches before you hit a rock.

The hole you see there is about 6 inches deep, took me 2 hours to dig that deep.
I don't have issues with clay or sand in our yard, the soil itself is pretty nice. But we've got loads of rocks in there. Not anything big, mostly between a golf ball and tennis ball in size, but you can't drive a shovel in more than 2-3 inches before you hit a rock.
The hole you see there is about 6 inches deep, took me 2 hours to dig that deep.