It's a lens thought for those who absolutely want 2.8 for "prestige" (as if one ever shot landscapes at that aperture...) but who have limited budget. As a consequence, absolute quality comes second place...
The Z 14-30/4 S makes much more sense to me, as I never shoot it below f/8... And yet, so many people don't want it "because it's not 2.8", a purely psychological reason (and note that I come from the legendary AF-S 17-35/2.8, but I don't miss it).