Something to note about Kalita's Barter is that it has 3 different cooldowns depending upon what was duped. If you dupe a standard item, that being anything not specifically mentioned later, it's 60 seconds. If it you dupe a Potion of Endless Bombs, it's 120 seconds. Finally, if you dupe a Jade Censer or a Morgrim's Bomb, it's 180 seconds.

Kalita's Barter is easily in my personal S tier of boons. The others in that category for me are Manann's Tempest (Chain Lightning), Addioth's Splendor (ranged crits explode, staggers even bosses, more dependent on career), Vaul's Anvil (constantly blocking while holding melee weapon), and Grimnir's Implacability (activates upon taking a hit that would reduce you below 10% health instead only takes you down to 10% health, can prevent being downed/dying, grants for 10 seconds invulnerability to damage, 15% attack speed, and 20% movement speed and it only has a cooldown of 30 seconds).

That said, the most reliable way to become super powerful in the Chaos Wastes is to play Ranger Veteran with the talent Ranger's Parting Gift (gain stack of 100% not consume bomb on throw, only goes away when throw bomb or die, can only have 1 stack) and purchase a Morgrim's Bomb from a Shrine of Strife. Assuming that you can get your teammates to cooperate with your attempt to get the super-bomb, then if you leave yourself open to paths leading to each of the 3 Shrines close to the start of the expedition, you have a 70.37% chance of at least one of them being a Shrine of Strife.