Maybe it doesn't actually double dip but makes INT scale better when an element gem is socketed on BB compared to STR. Test i've done: removed all gear but my test BB with a socketed red gem. Respecced stat points and set all to STR and checked damage on tooltip. Respecced again and set all to INT and damage was higher. Not a lot but it was a 20% gem (so lowest quality) and i'm still lvl 30 with a 300-ish GS gun. So i expect the difference to increase the better gear i get.