Cause if you'd think Dex is only for bards to parry with low strength then sir you are so sorely mistaken... And you won't even be able to comprehend why a Full Darksteel with Dex attached materia tank has almost the same EHP but lesser Emnity generation than Allagans/AF2. And also the reason why any Tank giving twos about their gearing will go full Crafted Accessories than Allagan or Myths.

The Dex research is to find the plateau of a % jump if it was linear then the research is no needed as it would effectively mean you have more dex? Good!