When using the default overlapping detection methods, even with colliders, if the speed or the animation is too fast, the intended collision can be skipped entirely.

This is the case for small bullets against thin targets or weapon swinging animations that are too fast or scattered.

This system allows you to trace between positions and determine if something was hit.

The difference between this and the free plugin is that this actually comes with a complete set of parameters to use with cross-linking tracing methods. This means you will have less chances of missing the target.

The difference between this and the blueprint plugin is performance. This can be used extensively on multiple objects whereas with blueprints, it's way more costly and limited.