@cm @FritzAdalis @alex @pseudomonas @chiffchaff
Well, if they want opinionated: a general calculator app should not return results that vary with an external parameter, such as currency rates, so it should not include currency conversion as core functionality.
Further, any general app that does currency conversion, _must_ let the user set the conversion rate, because there is no correct answer to what rate to use. By all means let 'use current rates from the Internet' be an _option_.