Without rationality, we are unable to know anything.
If we don’t have knowledge, we are unable to act confidently since we do not know what the result is likely to be.
If we are unable to act confidently, we find it hard to do things we have not done before.
If we cannot do things we have not done before, we cannot grow, develop and evolve. Eventually, as the histry of evolution has shown, those that do not adapt to change perish.
If you perish, your opinion on whether or not rationality and logic matters is irrelevant; shut up dead guy!