Having been in the art business, I have seen auctions with a reserve as commonplace.
While there is merit in not having one as was pointed out, it is only an isolated incident. You must also consider what we call auction fever.
There are times people decide that there is an item they MUST have and a bidding war begins. Some people will not allow themselves to be outbid by only a dollar or two.
With a high starting dollar amount you may never get the first bid. Having worked up to the reserve one might have the mentality of .... What the heck, i'm in this far, what's another few bucks?