It strikes me as funny how we want to get super AI inteligence but keep trying to anthropomorphizing all AI aspects to make it more "human". IMHO, if we keep doing it we will create Human AI with all errors and deficiencies humans have.
It's obviously the latter, a system that 'remembers everything perfectly' is probably not optimal in most senses. Mortality is a property of both life and artificial systems, forcing the same retention policy on new information and old information probably does so at the expense of lifespan or stability.
I think design-by-nature is consistent with seeking perfection, of course it won't ever be achieved, but organic inspirations can and often help maximize a lot of parameters.