It is often said that related experience is the number one factor employers use when hiring employees. An intern who does a good job may receive a glowing letter of recommendation. Sponsors like the enthusiasm and dedication of their student interns as well as the feeling of serving their community. Sometimes an intern can do an important project for a sponsor, one that may not have been able to get done by regular personnel. Your advisor will help you with your choice.
Any internship seems to be of benefit to a student.
But, by far, the ideal situation is where a student has a hint of what he or she may like to do for a living and takes on an internship somehow related to that field. Professions Are There, Honestly.