Because the room with bunk beds offers the option of having separate beds for more privacy when shared by two people.
Dinners and suppers are included. You are therefore responsible for your breakfasts.
Yes, there are refrigerators available for you to store your food.
In the chalet, you have access to two shared full bathrooms including toilet and shower. For the dormitory, you have access to a shared heated outdoor full bathroom including two toilets and two showers. You must therefore get dressed to go outside to the bathroom. A dry toilet is also available inside the dormitory for nighttime use.