Werner's cardioid projection is the limiting case of Bonne's projection when the standard parallel is a pole:
It has an attractive appearance, but is little used except as a novelty, particularly considering that it puts the area of minimum error in a part of the map that is unavoidably interrupted.
This projection is usually classed as pseudoconic rather than pseudoazimuthal, as would seem consistent: instead, the term pseudoazimuthal is used for more exotic types of projections, such as the retroazimuthal and loximuthal projections, and possibly also the Gnomonic when it is compressed along an axis to allow two points along the axis to serve as centers of the projection.