My guess is there are a few reasons. 1) He simply had one available for some reason, probably from a donor, 2) it would attract kids and 3) it will be used as a symbol of what "real science" can accomplish.
You mean not everyone has an A-10 in their garage?
I thought it was because the people most likely to be Creationist are also the same people that think they need to be armed to the teeth so they can overthrow the government when it becomes corrupt.
Maybe it's like one of those signs you put in your yard that says, "This property protected by ..."