it weakens, then you get the catalyst for void overshield and it does something different than buried bloodline.
Different strokes for different folks.
Personally, I'm not using my exotic slot on a shotgun in pve unless it's tractor cannon.
Pretty much everything it does can be very easily done by a legendary shotty and a bit of buildcrafting though. It just doesn't feel worth sacrificing my exotic slot for, when I could do the same thing with other weakening effects and a legendary repulsor brace shotty, and then use my exotic slot for a real exotic. I want to like the gun, it just feels too lacklustre at the moment.