I think Spanish peanuts have a reddish "layer" over the actual legume/nut. It's
kind of like the outer most layer of an onion.

If I'm not mistaken, that "layer" contains some resveratrol. A chemical that
may have some health benefits. I don't know how stable the resveratrol is in
that form but it's apparently present nonetheless.

That's the up side. The down side is that they're messier to eat!