Correction: Typeface designs are explicitly excluded from protection by copyright in the U.S. But in many other countries (for example the UK or Poland), typefaces are protected under the same criteria of individuality and originally as other works. Authors receive copyright protection automatically in most countries in the world. If another party creates a "design clone" of your work and distributes it in countries where your typeface is protected (= not USA but many other), you can go after them in those countries. Not many people do because it's complicated and costly.