Advantage of cleistogamy is

Cleistogamous flowers are not dependent on pollinators. These are bisexual flowers which never open, i.e. always remain closed. In such flowers, the anthers and stigma lie very close to each other. when anthers dehisce in the flower buds, pollen grains come in contact with the stigma of the same flower, i.e. autogamy occurs. So, these flowers produce assured seed set, even in the absence of pollinators.