I'm not saying it's about just the font being legible, that's such a small part of it and that's exactly what the opposite of my point again, there's a lot of other considerations with technical issues/restraints and debt to be had especially with production that designers need to consider as well as much more complex considerations in sequential design if it's a book. If you were doing signage for a museum or other public space and you have to consider the wayfinding system, legibility is the least of worries. You'd be using similar practices of expectation, navigation, iconography, etc to help people get to or perform where they want to be—and it WOULD matter. If you're doing a map, if you're doing a reference book, you will have to think functionally before visually. Remember the 2000 election fiasco of the butterfly ballots? that was print design gone wrong. Readers are still users.

But my point being is that functionality is deeply ingrained in all of graphic design—maybe it's more obvious in interaction design but I reject the phrasing that this is unique to interaction design and I think it's important to mention this because I've observed this air of superiority that some interaction designers think to have thinking they're above "graphic" design which is ludicrous. When I was doing mostly print design and someone told me in order to transition I'd have to think functionally more than visually I'd think they'd have no idea what I do.

And where this fits in with your discussion is that it's going to hurt your message and it certainly won't help your cause. I suggest you saying that the technical and functionality concerns are different but not that unique to this area of design.