Why tee up the ball at all?

[Weightshift]

2-J-2 INSIDE-OUT IMPACT ...
The ball should always be struck prior to the low point of the Downstroke, even when using the Driver, except under special conditions or to produce a special effect, which is a separate area of consideration.

When I see the pros hit drivers they leave the wooden tee in the ground undisturbed. So if the bottom of the ball is level with the bottom of the driver at impact, why tee the ball up at all? I can understand that if the teebox surface is irregular it might be necessary to tee the ball up a little, to clear the irregularities.

Also, I often see players using long wooden tees of 4" or more, so are we no longer concerned with the lie angle of the clubhead when hitting the driver?