At 25 DPT, the Leeching Shot Sniper has a lower Gold-to-damage ratio as the Sniper Monkey (40 less ATK for 2 delay), but it also gives a constant supply of Bloontonium. Like the Miners, this Sniper is a good candidate for maximizing Bloontonium gains throughout the game.
It has the same Bloontonium-per-turn rate as the Bloontonium Miner, but it cannot generate Bloontonium if it is stunned or there are no targets. Unlike Miners, it can generate more Bloontonium with ammo-granting cards such as Try this! or Quick Reload.
Its damage per shot is better than both Miners, but it has less overall DPT than the Mine Supervisor.
Equipping Leeching Shot Sniper also provides more Bloontonium-generating Monkeys other than the Miners; Mine Supervisors depend on basic Miners to maximize gains, and therefore sacrificing Leeching Shot Snipers is less of a downside.