Isn't a naked or near-naked woman used to attract straight men in advertisements? For cars, alcohol and other guy stuff? So who's the audience here? I wouldn't think lesbians are that significant of a market, even for this particular product.
Possible reason - men control the TV clicker, but their wives/GFs will also be seeing the ad with them? Though frankly, wouldn't most men find this ad TMI, naked spokeswoman or not?