I think there's very little benefit to a buyer other than the emotional one of knowing that when/if your home sells, you have a place to land next.

IME, a contingent on sale offer may not disclose what a seller is really willing to take for their home. I've found that many sellers are less negotiable for: "I'll buy when/if my home sells" than "I'm ready to go, are you?"

Also, at least in our area, the buyer will have to spend some bucks while in contingent status - home inspections, loan application and potentially an appraisal on the property and maybe fees for their attorney. Perhaps other costs in other parts of the country. If the contingent home fails to sell, or if the buyer gets bumped off the home, that's lost money.

Again, in my area, we have a lot of opposite direction contingent on sale buyers - those downsizing and trying desperately to sell their more expensive homes and stay in a community or school district. Joel makes a great point: regardless of if the buyer is contingent on moving up or moving down, it's vital that the contingent home be sellable and priced better than right!

The benefit to a buyer would be that they get to negotiate the deal, and know exactly what the seller will take. That can help the buyer in turn make critical decisions with regard to the sale price of their existing home.

Benefit to the seller is often that the buyer's home is less expensive, and therefore more likely to sell in today's market. There are downsides though. Never accept a contingent sale as a seller without checking out what the buer has to sell, and what they will be asking. If it seems like the buyer's house would be more difficult to sell than your house is, you probably shouldn't do the deal.

Most of the time, when the 48 Hr. Contingency is attached to the Purchase Contract, the buyer does have a house to sell. Once an offer is accepted with a 48 Hr. Contingency, the house "Usually" remains on the market. If another offer comes in that is more favorable, the seller then contacts the buyer through their agent/attorney to give the buyer 48 Hours to tell the seller if they can purchase their property, if not, then the seller is free to accept the 2nd offer! The buyer and seller are taking chances when doing a 48 Hour Contingency. But, the seller has a "Sure thing", since they have an accepted offer, while their house stays on the market, in case another offer comes in. The buyer is taking the bigger risk, since a better offer can come in and push them out, if their house hasn't sold or they aren't in a position to remove the 48 Hr. Contingency.