Advantage of cleistogamy is

The advantage of cleistogamy is that it does not require any pollinators as it is pollination in closed flowers.

(2) Cleistogamy has no role in vivipary. 

(3) Cleistogamy does not bring about any genetic variability as it is a contrivance of self-pollination or self-fertilisation in angiosperms.

(4) Cleistogamy does not produce vigorous offspring as it is a contrivance for autogamy.