Can't say for a VW, but my wife has a 2005 BMW 330 convertible and we have a wind block for her car. Makes a huge difference in the air swirl that comes around the back of your head and causes her hair to fly all in her face. When it is a bit cooler out, it keeps the inside of the car warmer with less air circulating around her feet.
I know they are expensive, but if you drive with the top down above about 35 MPH a lot, especially at highway speeds they do make a big improvement as long as you do not need the rear seats.
Some of the wind defectors are expensive because they have to fold to fit in the trunk. Not sure if the Beetle deflector will fold to fit in the trunk?
One issue with the BMW wind deflector is it can fold back when driving, so most people modify them by drilling 2 small holes for hitch/hair pins to be installed so the vertical part of the deflector will not fold back when driving.
On the BMW you can raise and lower the top with the deflector installed and the vertical portion up.
I assume you could open and close the top on the Beetle with the deflector installed and the vertical portion up??
Not sure why this small detail is never fully explained, but it is important as I would not want to remove the deflector ever time I needed to put the top up.