It might seem cool but the reality is that most probs don't even know the feature exists and I bet 90% of gaylander drivers couldn't even tell you why you're able to open the rear window. Therefore, they probably haven't thought of any practical use for it. Thus, making it completely useless for 90% of gaylander drivers. Personally, I wish it was just a plain old simple door. I've never seen anything as ridiculously over-complicated in my life.
When it's all iced up in the winter, you may as well pretend you don't even have a tailgate door because chances are, it won't open. (door can't open unless rear window drops half an inch) Which is really useful when you need to get your tow rope out the back to recover a Nissan Micra in the snow. Guess that's what they call Land Rover engineering!