To limit the probability that the load combinations used for the structural design will not take into account the case of the principal load acting alone, which could lead to structural failure, which could lead to harm to persons.
To limit the probability that the expected counteracting loads will create a force that exceeds the stabilizing resistance of the dead load for the case of the principal load acting alone, which could lead to overturning, uplift or structural failure, which could lead to harm to persons.