Well, there's also an exposure thing - the English version on DLsite only sold 400 copies (though the original JP release sold over 12K). I'm going to guess that since Kagura Games stuff actually gets on Steam, it'll reach a broader audience of English perverts. Of course, Steam doesn't post the sales numbers like DLsite does.
(That and Potato Life has only ever done two games, and their other "game" is a visual novel with an enormous number of rapey bad-ends. Actually seeing that translated would be nice but I doubt that's ever happening.)