/AMPRNet / HamNet routing is quite complicated for a non-IT guy... /
/The advantage of using BGP even in this trivial case is... /
I don't think the most important question is about selling BGP or any particular technology (I'm well versed in internetwork engineering and worked in that field professionally for many years; I'm in academia now).
I'm writing this because education was a specific question in the survey.
The reason that we have amateur radio is to enable experimentation with using the radio spectrum in a way that is otherwise not permitted or practical. With the Internet, there are certain things that are only possible to experiment with if you have your own addresses and other network numbers. AMPRNet is (perhaps that's too strong, and we could say, "can be") a way of enabling a kind of experimentation on the Internet similar to what we do with the radio spectrum.
It is not clear to me what you are getting at here! These are different layers of the cake. Your radio experimentation will result in some way to transport bits from A to B, but not in a network. To build a network you need another layer, and a way to define what you need to send where to get your message to the destination. That is what BGP is handling. By using BGP instead of static routing, we can connect many radio links and other links together and make a network out of it without getting buried in manual routing chores.
Please make sure you understand that the use of BGP I am mentioning here has nothing to do with the use of BGP on internet to route all the internet networks. It is the same protocol, but they are different use cases. Don't get confused when people say they have their AMPRnet subnet BGP routed to them on internet, and other people propose to use BGP internal to the AMPRnet network to route things the correct way, these are two different things.
Rob