The only reason that comes to mind is that Ed Smart considered Ricci a VERY trusted person/friend.
Also, about giving him the vehicle in exchange for "handy-man" work. At minimum wage for such work, it seems like a pretty darn expensive trade-out -- unless Ricci did more for Smart than has been revealed.
The other vehicles, which already have been checked out and released to Ricci's family, are a 1992 tan, four-door Ford Taurus and a 1995 white, four-door Oldsmobile Cutlass.
Wonder how the rest of the payment was made?