Why would you put bones in a scene?

[ChaseNJersey]

I downloaded a free background for anime studio, it is just a class room scene. Once I opened it inside of Anime I noticed that the room, the chalk tray, and the large teachers desk are all regular layers/groups, but the section of 8 desks are all in bone layers but contain no actual bones. Two questions, why would you but each desk in a bone layer, and what is the point if there are no actual bones?

I got the background from contentparadise under the anime scenes and props, its the free one labeled classroom. I am a new user and wanted to see how best to set up a room and I am just curious as to why you would use the set up with bones as in this file. Also, is it better to set a room up moving different parts along the z axis or is that just beneficial if you are going to zoom the camera in and around? Thanks again!

Michelle

[sbtamu]

The person that made it might have been using 'Debut' when making the chairs and Debut does not have group layers so they used bone layers that can do the same thing as a grp layer.

[funksmaname]

either way, bone layers are just group layers with extra possibilities.
When using a group layer for example, you could manually rig each desk to a bone and then use those bones to re-arrange the scene. You could also use those bones to make the tables react if they are knocked against or whatever. There are only disadvantages to using group layers instead of bone layer as far as I can see it, even if you don't put any bones in...