The problem is that websites are the most accessible way to deliver an interface for humans. But nobody else can do anything with the tech, and you're limited to the one workflow that the creator had thought of.

If this were a library or a command line app like pngcrush, web services could be spawned from it in days, easily. Or desktop apps. Or editor plugins. But in the current format, it's inextensible.

(disclaimer: this isn't always true, but it's true in this case)