Author here. Happy to answer any questions or concerns!
I wouldn't mind seeing more concrete examples, perhaps distilled from Prismatic's codebase. Macros are one of those topics where several real examples are super useful in demonstrating how it is more broadly useful than people initially intuit. It's one of those "Gee, that's cool and looks pretty useful, but off the top of my head I can't think many ways in which I'd use that in my own programming projects. I wish there were enough examples to deduce a generic pattern that naturally comes to me when working on my own code."