Wouldn't it be nice to sell your home without the hassle of exposing it to the public? Selling off-market works occasionally, but most sellers who try it eventually end up having to put their home on the market. This wastes time and could delay the sale.
There are other drawbacks to trying to sell without full market exposure. One is that it's difficult to prepare your home for sale if prospective buyers are coming through. You have to stop work, and buyers see a work in progress.