Perhaps their relatively short lifespan and lifecycle after mating is somehow correlated with them being around for 500+ million years. Somehow I find that more fascinating.
I feel like humans are inherently lower on this scale: we definitely live longer but I wonder as a species if we would be better off with shorter lifespan (and life cycle) like octopuses that helps the entire human species survive (peacefully?) as opposed to an optimization around single individual lifespan.