You might think why would one needs a aluminum wheel hex. The plastic ones works as well. The answer is yes, but the plastic one is annoying to maintain. Everytime you change tyres, the plastic ones might get stuck on the rim, which makes it really annoying to remove. And with the plastic ones, if it comes off, chances are you're going to be losing the 10mm wheel shaft.
Another advantage of these wheel hex is you can get different sizes to offset your tyre position. This can be helpful to change your wheel position and make sure your car is race legal.