also financial: some people rely on blood donations for extra cash to pay for food and bills. Though, there are better ways to give people opportunities…
As I understand it, some hospitals offer payment for blood donations but if you want to get paid the most reliable options are probably pharmaceutical companies. By number of donors, both are probably eclipsed by the Red Cross though, which by its nature heavily relies on volunteer work.
What you can see from that is that a "Aufwandsentschädigung" of ~20€ is pretty common.
Pre-COVID the German Red Cross often would have a buffet lunch typically consisting of sandwiches and fruit for donors. Since then they seem to have moved to prepackaged lunches and branded giveaways. But never cash money.