As a development tool, it allows you to quickly build software that works the way you do. From simple one trick ponies, information managers, a custom accounting system designed specifically for your type of business, or even a commercial idea that could make you famous. SuperCard has been used for all of these and more.
As a presentation tool, it can free you up from the limited options most presentation tools offer. You can even use it to build interactive kiosks.
As a teaching tool, it can empower you to build classroom utilities and courseware that are truly compelling. And it is an ideal environment for teaching students to program; initially at the scripting level, and then using Apple's Xcode with SuperCard: Suite's Internals Toolbox.
But no matter what you want to build, you can be confident that SuperCard will take long learning curves and heavy grunt work out of your development. Interface design is a simple as drawing it out on your screen, and the actual programming is done in an easy to learn, intuitive, english based scripting environment that will have you up to speed in no time.
SuperCard is simply the quickest path from ideas to results.