The concept behind this idea is very simple. Instead of dragging objects from the toolbar, or ctrl+drag to duplicate, this tool allows pasting multiple instances of the selected object with a single click for each instance, much similar to stamping a paper multiple times.
Why? It is much faster that any of the current methods. It also allows what I call "brush based level building", which is a thing I really liked in an engine I worked with in the past. Instead of a tile-based approach, where everything MUST conform to the grid, and tiles can not be overlapped, this allows for more organic level building. Below is an example of what this method achieves. The screenshot is taken directly from a game running on that engine.
The grass part is made of multiple overlapped brushes, one for each tone. This made the terrain look very natural, and not so blocky like a tile-based approach. Putting this scene together took considerably much less time as any of my attempts to replicate the method in C2.
The last object to be placed has a greater Z index than the first, meaning Z is ordered from foreground to background.