Comparing Font Choices on 9 Mobile Apps — Custom vs System Fonts
amit malhotra

Hey, first of all—a very nice article.

I would just like to add on to your case here. The choice of fonts also depends on the user experience in the way that the native fonts should be used for apps, where people can upload content in the form of text (to support the variety of different languages), and the custom fonts can be used for apps, where content comes from the app’s creators (English language in the most cases).

I hope this helped. :)