Is vaccine important?

Absolutely. Just look at the history of the diseases being vaccinated for and you will see how deadly they can be. We sometimes underestimate importance of vaccines because (thanks to them!) we no longer have to live with the diseases they prevent. But they can and will come back if we stop vaccinating.
Yes. They can save your child's life from life threatening preventable illnesses.
Yes. All vaccines are given to protect the children and adults against common infectious diseases which can cause morbidity and mortality and are important to prevent these diseases.