“What? No, I didn’t illegally mod the holster. These are just really lucky pants!” – Cayde-6
If these Lucky Pants really did belong to Cayde, I expect there are a lot more hidden tricks than meets the eye. Tricks of the gambling and ramen-eating variety. The Lucky Pants are a Subclass neutral Exotic that is really only useful to the Hand Cannon using niche of Guardians.
The Lucky Pants hold the Exotic perk Illegally Modded Holster which increases Hand Cannon ready speed and initial accuracy. Basically, this means that your Hand Cannon will be ready to fire more rapidly after switching weapons and your first shot or two will have better accuracy than the rest of the clip. This perk is a simple yet handy little bonus for Hand Cannon users but due to its niche may not see much use over broader kind of Exotics. That being said the Lucky Pants provide a very specific service to Hand Cannons by making it quicker and easier to land the first shot. Many a time in both Destiny 1 and Destiny 2, the Guardian who gets the first shot off turns out to be the victor of the battle and the Lucky Pants will definitely be an ally in that regard.
I do have to say the Lucky Pants may see little usefulness in PVE. I mean a bonus to both ready speed and initial accuracy is a good thing no matter which way you cut it, but there seem to be a larger pool of more beneficial PVE Exotics to choose from. The Lucky Pants are far from useless, however, but with the state of Hand Cannons currently, in both PVE and PVP, it may be a bit meh. There are good Hand Cannons in Destiny 2 with my personal favourites being the Sunshot and Judgement but they seem a bit lacklustre compared to other archetypes.
Nowhere is this truer than in the Crucible, which is dominated by Auto Rifles, Scout Rifles and Submachine Guns. Not that this is a bad thing, with the meta the way it is, but with Hand Cannons kind of falling by the wayside at the moment, there may be better Exotics to give your Hunter an edge. Hopefully, Hand Cannons can make a triumphant return in Destiny 2 for both PVE and PVP which will see the Lucky Pants as a top-tier Hunter Exotic. But hey, you know your skills better than I do, so grab your Hand Cannons and prove me wrong!
The Lucky Pants can be acquired through an Exotic Engram decryption or from Xur if he happens to carry it in his inventory.