I am confused about 3d warehouse

I can’t understand the reason for having so many classifications: model, folder, collection, like, and favorite

1) from the user’s point of view: in what specific situation should each of these tools be used to organize what is perceived to be useful in the 3D warehouse?
2) what is the difference between a “folder” and a “collection folder”?
3) how do I “save” the entire collection like the shown in the second screenshot?

It seems to me that there is an attempt to make 3D Warehouse an intuitive and easy to use tool and keep everything organized (something like Pinterest), but I am still confused to do some things that I think should be extremely simple.

First screenshot:

Second screenshot: