What I mean when I say I don't know what 'honest' means, is that I don't think that people using that word mean that a house clad in vinyl siding that looks like it is clad in vinyl siding is honest. Nor do they mean that Roman architecture of the classical constructed as opus latericium [1] is dishonest (or doubly dishonest if is still clad with marble).
I don't think 'honesty' (and 'functionality') are an improvement on the Vitruvian, 'firmitas, utilitas, and venustas'[2] for no other reason than Vitruvius backed the concepts up with examples and the examples included everything from fortifications to bridges to temples...which in map pretty well as typologies in which each takes priority over the others.
Perhaps it's because Vitruvius honored those generals, the city, and his gods rather than bricks.[3]
[1]: https://en.wikipedia.org/wiki/Opus_latericium
[2]: firmness, commodity, and delight
[3]: https://www.yatzer.com/even-brick-wants-be-something-louis-k...
Well, they did provide a definition for "honest" - that it looks like it's built with the materials it's actually built with.
Of course, so did stone houses for centuries, and they still managed to look pleasing in the process.