With levels you could, for instance......
Have 3 all at the same elevation but different heights, effectively giving three ceiling heights
A further 3, each with an elevation to match the ceiling below, your roof's.

Taking into consideration one of your other posts, make this 6 or 9 levels with the same floor/ roof set up as the first.
You could now position walls doors windows etc in the 1st, copy them to 2nd and 3rd thereby enabling you to change colours/textures and compare/change them in 3 different homes all in 1 file, no more opening and closing.
File could get very big very quickly so I would advise avoiding things like plants and trees.
May help

Mike