The inverted commas around the word "death" here are intentional.

A couple of hundred years ago, if you stopped breathing, they buried you. As recently as the 1950s, if your heart stopped, you'd be cremated. These days, it's more likely you'll be resuscitated and sent back to work to pay your taxes.

Science is constantly pushing the boundaries of what is considered "dead". Cryonics simply pushes that boundary a little further.

By suspending a (legally dead) patient's body in liquid nitrogen, it is possible to prevent further deterioration of the body indefinitely. For obvious reasons, the initial cooldown is to be commenced as soon as possible after the patient is pronounced dead.

The intention behind this is that cryonic suspension is a sort of "ambulance to the future". Chances are good that the treatment you will require to be revived will be available in the future (just look at how far humanity has come technologically in the past 50-100 years alone, and then project that forwards). You just need to be in some condition to receive the benefits of those advances when they are developed. Cryonics aims to get you there.

You'll recall that cryonics involves stopping the deterioration process that begins upon clinical death. You'll recall that for this reason it's best for the initial cooldown and preparation to be done as soon as possible after one is pronounced dead. That's why you'll be wanting a "Standby Team", with the training, equipment, and willingness to do that for you.