RE: finishing fused glass
These tools are used to do what is commonly called coldworking. They can be used to even out and then polish the edges of a piece, flatten the bottom so it sits evenly, remove slight imperfections, add texture…Basically give your piece a more professional and finished look.
There are a couple of books on coldworking “The Joy of Coldworking” (http://www.warmglass.com/joy/) and Coldworking without Machines (http://coldworkingglass.com/). The latter book provides ideas on how to achieve a nice finish with less expensive tools/methods.