NFL end zone pylon placement

[EndZoneEddie]

In watching the AFC Divisional Playoff game between the Chargers and Colts I noticed that the pylons were placed out of bounds. What is the point of this?

In a close play at the goal line, wouldn't it be better if the pylon represented space within the end zone and in bounds? The way it is, a player could reach the ball into the pylon before being down or out of bounds by body contact and it would prove that part of the ball was out of bounds after crossing the goal line plane but would provide no proof that any part of the ball crossed the plane in bounds thusly signifying a touchdown.

By the way, looking for the NFL rules online regarding the proper placement of pylons produced no results.