Allow you to create your own custom 3d font. Design your own unique font for company's logos or Opening credits or for other uses. If you have a specific font design in mind and, after looking at hundreds of fonts, you've concluded that you'd have to make your own lettering to get exactly what you want.

Your typeface might comprise of a limited set of characters because it's for a particular project or personal use. However if your aim is for it to be used by other designers, for a variety of projects, then it needs to be flexible and have a broad character set. This would generally include small letters, numbers, special characters and capital letters, to adapt your font to this tool, you need to use the "Extras" option.