The perks Armorer, Blacksmith, Gun Nut, and Science allow players earlier access to mods than they’d get by just waiting for drops, but eventually you can find most mods without needing these perks, making the perks feel less important. This just adds some small side-effects to them so that they never feel like you wasted a perk point.
Armorer: Worn armor weighs 5% less per rank.
Blacksmith: Melee (and unarmed) attacks ignore 5% of target armor per rank.
Gun Nut: Ballistic weapons have 5% increased range per rank.
Science: Energy weapons have 5% increased accuracy per rank.