That's a great point. It could still be something that is a nominal level of cost to a recipient and their insurance to the extent of covering all funeral costs plus a nugget (say +/- $10,000 for an organ).
I figure you don't want to make it too valuable otherwise there will be people/relatives "speeding up" the death schedule.
Donating something like a kidney, of which a health person needs but one, is different from donating a heart or an eye.