I wouldn't say this idea is particular to Oda, though. After watching the RE movie, I was motivated to play the RE2 remake, so Mr. X, for example, is supposed to be a super soldier, but despite being intelligent enough to know guns equal bad, he'll just walk up to anyone and try to beat them to death, as he knows he's invulnerable, as they shoot him. So, whether it's super toughness or regeneration, a character with such a power will constantly show it.
Does that make sense?