Why do people bother with an annulment when they can get a divorce instead?

Money. A final judgment of annulment or nullity of a marriage means that the party who receives it may dispense with support, property distribution and another other obligations afforded former spouses under the laws of the jurisdiction. In some jurisdictions, annulment resurrects rights a party may have lost as a result of an annulled marriage, including Social Security benefits and in some cases even alimony.

Annulments are "creatures of the state," which is legalese that means that each state sets its own criteria for an annulment; but many courts are reluctant to annul marriages when they can just as easily end them by divorce because of the financial implications to one spouse.