It is being said that organs can be obtained for transplant from the pigs. What is special about pigs that we are using them? Why can't we use monkeys or chimpanzees with whom we share a more recent common ancestor?
Monkeys and many other primates are too small to provide organs that will provide the needs of a human host. The fact that primates are so close to humans physiologically is not always a win as transplanted organs will bring diseases into the host that can be quite dangerous.
Besides, because even human human transplants induce immune rejection of organs. Its typical that immune suppressants will be a lifetime treatment for the patient.
Finally, the cost of a pig organ is negligible and their organs are about the right size, and I would bet that activists don't protest pig transplants nearly as much as primate donors.