Just to clear it up, the point of the hole isn't because holes are great or because they absorb sauce better or anything like that.
The point is just to get really thick spaghetti.
If you were to attempt this without a hole, when the outside was ready to eat, the inside would still be unpleasantly crunchy. Or, if you cooked further to get to the point where the inside was properly al dente, the outside would be an overcooked mess.
The only way to produce a thick, properly-cooked piece of spaghetti of consistent, uh, consistency is to remove the part in the center.
The point is just to get really thick spaghetti.
If you were to attempt this without a hole, when the outside was ready to eat, the inside would still be unpleasantly crunchy. Or, if you cooked further to get to the point where the inside was properly al dente, the outside would be an overcooked mess.
The only way to produce a thick, properly-cooked piece of spaghetti of consistent, uh, consistency is to remove the part in the center.