Using a line is becoming very common both on the greens and off the tee.
On tee shots some Pros have the line parallel to the clubface because looking down at it bothers them visually.
However, I would not take a manuf. at face value that the line is in the best location. If you put one of the most popular balls on a "scope" you will find that the line on the ball and the "scope" do not often match. Because of this, I am aware of one pro who wants all the balls he gets scoped by the manuf. before he gets them.