Every game world needs some boundaries.
Even if you already have some natural boundaries such as cliffs or roadblocks that the player should not pass through, it is better to seal them off with some invisible walls just to make sure that the player cannot glitch past the playable area.
You don't want the player to step outside of the intended game space and find poor quality background geometry or even immersion-breaking terrain edges.
With this package you can easily place and edit invisible walls in your game world.
If you wish, you can enable the proximity effect, which will hint at the location of the invisible wall when the player gets close to it.