First, minislot can be scheduled flexibly by using preempt scheme with a higher priority over regular slot for eMBB traffic. Thus lower latency. Second, minislot can handle HARQ within the same slot, which results in a very low latency. Within the minislot, the RB introduces more diversity mechanisms for the reliable communications, and the details can be refer to NR release 16/17.
The practical use case could be Industrial 5G equipment, medical robotics using 5G for robotic surgery, automobiles IVI systems, M2M etc where speed ( low latency ) does matter instead huge data for quick response