Why is the Dark Theme an in-app purchase?

Some users were wondering why we made the Dark Theme an in-app purchase, instead of including it as free update. Almost eight months after our initial release, we think it is fair to charge $0.99 for an non-crucial feature in an app many people use every day. 
Besides this, the free updated included many new features, such as the option to change weather data providers, for free. Thanks for your understanding.

Feedback and Knowledge Base