The information you will be able to gather from doing vetting of individuals include criminal records, educational background, employment history, driving records, vehicle registration, credit records, ID Number verification, court records, personal references etc.
Sometimes some applicants attempt to inflate the numbers in the salaries they claim they received from the previous employers hoping to get a higher salary from the new company they are applying at. Vetting helps you avoid these kinds of individuals who resort to unethical means just to get more money.
Vetting also reveals criminal records, which are also very important pieces of information to use for assessing an applicant. Surely, you do not want to employ someone who has had a criminal offense of fraud history to work for you as an accountant. You do want to hire a person who has had records of child sexual abuse to work for your business that offers children services.