Here’s the problem with living in space. You’re basically live in a large bubble. When you do finally make it down to the surface of some strange planet, your body has no idea what to do with all that tiny dust and debris floating around in the air. I don’t even know what those particles would do to someone with a robot face.
Just look at poor Vader here, one of the most powerful Sith Lords around, but basically crippled without his inhaler. Just one of those funny things. I really would have thought that sophisticated helmet would come with some kind of built-in filter, but I guess it was just made for the intimidation factor.