I understand the use of private auctions for some categories of listings, such as fetish items, erotica, some health and beauty, etc., but I've never been able to ascertain a legitimate reason why someone would do a private listing for something as innocuous as handbags and accessories.
I'm always bothered by most private listings, especially in auctions that start at ridiculously low opening bids. It's been many years since penny and 99-cent listings have encouraged bidding wars and most of the sellers I know who've tried 99-cent lisitngs have (for the most part) lost their shirts.
In looking at this seller's current, completed and feedback listings, most of what she sells are purses and wallets. And looking at the few "public" auctions, those selling prices seem to be lower than those you can see in the completed listings. While I have no idea whether there's any "illicit" activity going on in the private listings, I've seen enough shill bidding that I'd avoid those types of listings and the sellers who run them.
Another problem with private listings is that once those listings are too old to show in the completeds, we can't see what items the seller sold and whether they're authentic.
Though I've not seen this seller with fakes, private listings are another way for other sellers to hide the fact that they sold fakes. In looking at feedback, you have no way of seeing past history.
With so few items around that are really OOAK, when I buy, I prefer sellers who offer transparency in their listings.
JMHO.