Although popularly associated with the image of the ninja, the use of shuriken in the martial arts was also widely practiced by the samurai class- both flat bo shaped shuriken and star shaped hira shuriken.
What place does this training tool have in the modern day?
Well first off, throwing stuff is fun, and being able to take something in your hand, visually connect it to a target and then toss it and actually hit (or come close!) is a very useful skill. In our training we often use safe rubber shuriken as a way to practice tai sabaki- one training partner practices throwing them at another who practices dodging them using martial arts movement.
At first the thought it to try and hit the target where it is in the moment which means the person avoid the throw moves just ahead of it.
Likewise when practicing the throw speed is not always the best but rather lead time- begin the throw, allow the training partner to begin moving, and then continue the throw placing the shuriken in the path of where they are going.