My reading of the article is that the author has chosen to use "ANF" to describe a specific property of their IR that is not unique to ANF, whilst ignoring the fact that ANF (and variants of it) is strongly tied to the functional compiler realm where a specific tree-shaped structure - with nested and first-class functions etc. - is expected. The article says "It's an instruction-based, assembly-like, typed, ANF language". I think the usage of "ANF" is a misnomer here: just because it has this atomic arguments property does not make it an "ANF language" (whatever that means).

I normally wouldn't leave such a long - pedantic - comment, but the first comment on this thread was a question about ANF; I don't think much of the article has any relevance to ANF. It's mentioned off-hand and used as an adjective ("Bril is extremely A-normal form"), which suggests we need better terminology here. Most practical CPS IRs share the same atomic argument property, but you wouldn't suggest "Bril is extremely CPS".