Signing a donor card is pointless. Doctors may let me die so they can transplant organs to other patients. Every effort is made to save the patient's life before donation is considered. It costs money to donate. Donation is painful for the donor's family.
Donation disfigures the body and delays the funeral.
Donated organs and tissues are removed surgically, as in a routine operation. Most donations take place within 24 hours after death and therefore wouldn't delay funeral arrangements. My religion opposes donation. Transplants don't really work. They are experimental.