Why I built a dictionary app even with more than +300 apps available at AppStore?

Zeh Fernandes built a dictionary app even with more than +300 apps available at AppStore. The main challenge of having a good dictionary app isn’t tech or design; it is the license models of the companies that maintain and sell dictionaries. All pricing and licensing models I found so far are API based; they charge per call and forbid you to cache the result.