Grappling is a component of the JSK system and is necessary for advancement. You cannot train in self-defense and ignore the value of the ground fight, the ground is a great equalizer. The attackers ability to utilize their full power can become limited when you are forced to take them to the ground. A smaller individual, with the proper training, can defend themselves utilizing the ground as an ally.
Although this may resemble Jūjutsu (Jiu-Jitsu), the principle is different. In JSK Combat Grappling you are attempting to reposition yourself for proper defense and, if possible, get back to a standing position with the option to either continue to engage the attacker or withdraw.  
 
Self-Defense
The goal is 100% self-defense and while grappling you should maintain a mindset that your opponent may have various unorthodox ways of fighting which may include biting, clamping, gouging and classic strikes of all varieties. Never leave yourself open for a strike, your ability to recall technical skill is minimized after receiving multiple strikes.
Additionally, does the training you are doing on the mat translate to the street? Will it work in a variety of environments outside of the academy?  

Vet Your skill
The student begins by first learning a skill with a cooperative partner (uke), as the skill improves the partner will raise their level of resistance. The student then learns to apply the technique from a variety of positions. 

Sparring
Traditional Hapkido programs tend to ignore this aspect of training. I believe that this is a mistake, done properly and gradually, sparring raises the confidence and skill of the student while testing their knowledge of a particular technique.