Donating blood provides several benefits:
1) It provides a moral benefit by helping others in need of blood transfusions.
2) It benefits the health of donors by testing their blood and providing a new supply of blood which can help detect diseases.
3) Regular donors can benefit their health and earn money for donations, as some companies offer incentives like food rewards in exchange for donations.
4) Donating blood provides PR benefits for both companies offering incentives and public figures who donate, as it fosters mutually advantageous cooperation.