Or Switcheroo, Thief, Magician, you get the idea. A ring target can be tricked onto an opponent's Pokemon, for example Spiritomb. When holding the Ring Target Spiritomb is viable to fighting type moves, giving him two weaknesses. It can also be used against Pokemon that commonly run Thief, or have the ability Magician. Even so, this strategy isn't used that much, as a lot of Pokemon can hold better items than a Ring Target solely to trick onto foes that have immunities, especially because it isn't really needed, as you can target the Pokemon's other weaknesses.
Hope I helped!