This technique allows the user to suppress their or their allies' chakra to the point that it becomes completely undetectable. This makes it impossible for sensor typeshinobi to track them via chakra. As noted by Shikamaru, this technique is very useful in the sense of allowing the user to infiltrate the enemy's ranks undetected.
The downside of this ability is that since the user suppresses their chakra, they are unable to use ninjutsu. When Karin uses this technique, she is unable to use her Mind's Eye of the Kagura technique for example.