This is primarily to benefit those in their care who have allergies or compromised immune systems that preclude them from getting vaccinated themselves. These individuals can still be protected through "herd immunity."
One predictable outcome of significant pockets of society opting out of vaccination:
outbreaks.
Yes, this is one of the things that's very damaging about the "personal choice" crowd and vaccines. Most choose to ignore the fact that their personal choices can make other people, like babies, cancer patients, and people with allergies, sick or very sick.
