i use coconut milk/cream in a lot of my cooking, mostly thai or indian cuisine as a replacement for heavy cream.
coconut milk is the juice + the meat of the coconut liquified together
coconut juice is the water inside the coconut
for drinking, coconut juice is the preferred choice.. but its not like dairy milk at all.
i put almond milk on my cereal or in a smoothie, sometimes i use it with baked goods as well, i think its the closest thing as a replacement for 1% or skim milk, imo.