Answer: It is a unique opportunity and a valuable experience for the future.
Explanation:
It would certainly be useful for the graduates to volunteer. This is a valuable experience for the future, and a unique opportunity for the students to do some of the jobs which are listed. They are unlikely to volunteer at hospitals later in life, unless they opt for a medical discipline. Moreover, majority of the students will not choose a career of working in a park or repairing homes, and especially not a military career. This is, therefore, a good opportunity to try something new and out of the ordinary. As a result, they will acquire certain working habits, and see what it is like to have a real responsibility. Finally, they will be able to earn extra money, which, for some students that come from poorer families, is a great advantage.
"Just to clarify- for those that do not know" (I will continue in the comments)
