A font change is not a concept
Two typefaces are not two concepts. A concept is a genuine creative territory — an idea, an intended perception, a visual architecture, and a risk. House of ARA does not present the same lockup in a serif and a sans and call that a choice.
A concept must have an idea before it has a polished mockup. Routes shown to a client are actually different, not a change of tracking and colour.
How territories differ
Paper, Material and Sequence are house examples: each holds a different idea about how an identity should behave. A client project produces territories of its own. Typography is a primary brand asset — it is not the whole idea.
What fails
Decorative luxury — serifs, black, gold, wide tracking — is not a substitute for judgement. A mockup is not proof of a weak mark. Forced negative space and arbitrary monograms are not concepts either.