I don't know why some people chose to use it. I used it once in a listing of mine when I was selling some vintage gay men's magazines (Now I KNOW that sounds bizarre...DH and I were at an auction shortly after we were married to buy antique furniture...this box of mags came up for auction and no one was bidding on them...we thought they were a hoot, with pics of men in loin cloths 'wrestling' so we paid about $4 for the box...looked them up on Ebay and found that they sold for $50-$60 an issue!). Anyways, other people selling these mags were using the private listing so we did too. I suppose anything that could potentially be embarassing to the buyer would fall under this category. Otherwise, I don't know!