Ok, newbie question...why do I need one of these? Cuz if the Dis says I need one, then clearly I do, but what do I do with it?
Oh wow, I am in the minority but I don't think they are needed at all. Same as you, first cruise I took one because the Dis made me think I did. I never used it. 5 people that time and there was plenty of shelf space in the bathrooms.
Next time 2 people and again no need for that.
At home I don't hand my deodorant in a packet. Next to a pocket with a razer, and a pocket of Advil. It's just all in my make up bag which is how it sits on the shelf in a cruise bathroom.
While small, they are exceedingly well thought out in terms of shelves and storage.