Sure, when C++ was conceived, I imagine the only thing Stroustrup had in mind was error propagation. An extension of existing concepts drawn from software and hardware facilities of the time. So what? For me it is a tool that can achieve many interesting and useful things and so I use it as such. A bird's feather, after all, was not "designed" to be a writing instrument and yet it was nonetheless adapted to do so. Nothing on this earth in fact would have found utility had someone not stood up one day and said "I know - I'll use it for this!". Sorry to wax philosophical, but for me the subject is just that.
In "most" cases, perhaps, but certainly not all. Checking a flag repeatedly within a loop or calling a bunch of "structured" functions may well be less efficient at times.
Obviously I am playing a bit of the devil's advocate here. For the most part I think my code, by virtue, "tends toward the convention". I just want to make it clear that I do not subscribe to nor promote any sort of "idiomatic usage for the sake of convention" type approach to programming. The mathematical beauty of a well written program transcends and trumps that any day.