I was in home furniture manufacturing for 25 years and also in Super Yacht Furniture Manufacturing for 2 years. When speaking about furniture "not built into a boat," the industry refers to it as "loose furnishings."
The main difference is price
. The other difference is that furniture used in homes is not restricted much by the size of the area where placed, while size is important for furniture used in boats
If the "loose furnishings" are going to be in a moving, tossing, and turning environment
, they need to be secured, whether they were made for boats, or not.
Hope this helps.