Well, in actual fact BBMF does cost a lot. Okay, not much in the wider scheme of things, but when it is money being spent on nothing that has any defence application, it's a waste by definition. All very nice of course, but unnecessary. If I thought for a minute that the BBMF aircraft would otherwise be lost forever then okay, that's a different matter. But when we all know they'd survive and flourish in civilian hands...
As for the wider significance of the BofB, you have to bear in mind that it's not quite so significant for a younger age group. One could argue that the V-Force is just as significant if not more so. It's a proverbial Pandora's box, when one starts making judgements as to what is significant and what isn't.