There are arguments for unique IP addresses for interfaces. I'm just amused at the addition of yet another layer of address indirection.
Certainly, I'm convinced that neither you, nor the fine folks at BSD were/are clueless about these things. I think it's important to know why these decisions were made, and what trade-offs were involved, so that I don't get dogmatic about them.
I'm not one to defer to authority too easily, but it's my experience that, when someone with enough experience says something that sounds out of this world, it's a good idea to think about it for a bit.