That just means that you would get "at least" an oceanview balcony cabin.
There are some less desirable cabins in that category. On the Adventure, the balconies are part of the superstructure. They are not exterior to the skin. So the balconies are somewhat "cavelike", but particularly so on Deck 6, where there is metal on the bottom of the outer facing wall. Deck 7 & up has plexiglass.