Sigma launches new ART versions of their 30mm and 19mm f2.8 and new 60mm f2.8 lenses

Sigma's choices of 19mm, 30mm and 60mm focal lengths make more sense to me when I think about what must have been their major considerations/constraints of design:

1) not to duplicate FL of existing/planned Sony e-mount lenses such as 16mm, 20mm, 24mm, 35mm and 50mm, all but one of which are faster than the f2.8 max aperture of Sigma's lenses;

2) single lens design to fit both mirrorless systems, one with 2x and the other with 1.5x crop factor--hence 60mm rather than 75mm because latter FL would have been "too long" for a portraiture lens in m4/3 mount;

3) single lens design for both mirrorless systems again helps explain why no optical stabilization...because at least one of the major m4/3 camera lines (Olympus) already has in-body stabilization.