Right now they can edit the ad title to achieve the same thing.
It would be nice to have a standard On Hold status display that can be assigned (just like Sold It!), and also removed if the item goes back to being available.
I have a lot of sellers who will negotiate with buyers and agree to extended payment terms on higher value items. They like to keep the item visible in case the buyer doesn't come through. A second potential buyer may ask to be put next on the list, and that helps avoid further delays if the first buyer doesn't make good on the payment agreement.
Hope that makes sense.