How to pick a typeface for user interface and app design? 

TL;DR: Make the Il1 coe test to check whether a typeface is suitable for functional text. Il1 should be easy to distinguish and the apertures of c and e should be open.

Il1 coe
Il1 coe
Il1 coe
Il1 coe
The Il1 coe check.

Oliver Schöndorfer makes some points in his article How to pick a Typeface for User Interface and App Design?: