After the failure of the Cryonics Society of New York (CSNY, not to be confused with this or this), due in part to their acceptance of cases whose families promised to pay in installments but later reneged (causing them to run out of money for keeping their other patients cryopreserved), the remaining cryonics organizations require ironclad assurance of payment for suspension. That's really hard to arrange if you die without a few months' notice, even if you have an insurance policy, since your beneficiaries won't have the money to give to the organization for a few weeks or months after your death (for which time you'd be on dry ice, and undergoing a small but worrisome amount of degradation). Naming the organization as a beneficiary gives them 100% assurance that the suspension will be paid for, and without that they won't send out the suspension team.

(Someone correct me if I'm mistaken in this account.)