Well, Attributes have options and these options can have a different language per storeview.
So if you are creating the Option 'Wine' and afterwards you have a German and Dutch storeview, it will be shown in that row as:
> Wine,Wein,Wijn
And when you later select another option, for instance 'Cheese' which is also translated it will say:
> Wine,Wein,Wijn,Cheese,Kase,Kaas
Do you see how quickly this become confusing when you add more and more options? And even the order matter, so it also can be:
> Cheese,Kase,Kaas,Wine,Wein,Wijn
And the custom filter, with many options selected, will have you select the *precise* order.
It is not practical.