Your concerns are the reason why I actually learned skills so I could contribute to the medical team. There are only so many beds you can make, and blankets to distribute as a volunteer before you realize that you want to be able to work closer with the team. It's not all like this, but it seemed it at times.
As for necessity, it depends on the school(s) and the rest of your application. One thing is for sure, it is never a bad thing unless you do not prioritize your time effectively and you drop the ball somewhere else. Some schools really look favorably at clinical time to help alleviate their concerns that you know what you are getting into. An advisor for my state med school talked to our undergrad class and stated that they typically "expect" 500 hours of clinical time, although it is not required and I know of people who have gotten into med school with much less or none.
Regardless of necessity, it is a very good way to become accustom to the medical environment and patients. Also, you become very close to the doctors and can attain stellar LORs from them (not from speculation, but from real experiences). Also, some people find out that they can't stand dealing with sick people or bolt after their first trauma. It affirms that you understand the profession you are trying to enter. I could go on and on regarding the benefits of good clinical experiences, but I'll leave some other topics for others.