I wonder what the rationale for taking the tank was? Sounds like the Iraqis were using it to teach the tankers how to drive. (I didn't follow that psychological reason the Iraqis were supposedly using the tank for.) Iraq's rebuilt military will have an armored component, won't it? They could still use the old Sherman for driving practice.
I guess the theory is that it is a war prize? "I want it, so it's mine" doesn't sound like the right policy for a liberating power.
Anyway, it would certainly be an interesting subject of a diorama, as it proudly drives past Paladins and Bradleys and Abrams(es).