Not sure exactly what you're referring to, did the author explain in the past they rather want ad-hoc network setup or something?
Otherwise, ad-hoc is different from AP+Client, as ad-hoc is only between two devices (at least from what I gather) while AP+Client would allow a distributed network where clients are interconnected.
It's extremely rare that one gets to a working ad-hoc setup... it's a chicken-egg problem. Drivers, firmware, software and UI support are bad, so no one uses it, so development is an afterthought, rinse and repeat.
ad-hoc in general runs a different path inside kernel module, which is normally not supported as well as AP/client mode, so, while many chips can do ah-hoc in theory, in software side it is a difference story
Otherwise, ad-hoc is different from AP+Client, as ad-hoc is only between two devices (at least from what I gather) while AP+Client would allow a distributed network where clients are interconnected.