Because its literally free ammo guranteed. Its very beneficial in cases for nightfall strikes/modifier or gambit where I deplete special and heavy very very often against a crowd of adds or yellow bars or Champions and special ammo drops doesn't drop often . I loss count how many times special ammo doesn't drop for me. As a person who solo farm hallowed lair, special/heavy ammo is the most important resource over demonitionist or elemental capacitor.lead from gold is pretty good?
I tried to picture how it would work and why I would choose it over Elemental Capacitor or Demolitionist. I couldn't really imagine a scenario where it would feel like a better perk than those.