These are fun. We have one in a home and the kids absolutely love it. Completely impractical but definitely adds something to the home. Nice party trick for folks too.
We have access to storage space in the roof through a door in the back of a closet (only hidden by the clothes hanging in it) - we call it the "secret passage" - our kids always won at hide-and-seek when their friends came over (well at least the first time)