I've only come across the phrase 'straight in approach' during my military flying career. It was invariably used to highlight that the aircraft would be positioned (either via ATC or self-positioning) to a long/short final position (on the Rwy centreline) where the aircraft would be configured prior to landing.
If the aircraft was not being positioned for a 'straight in approach' then it would invariably join for a visual circuit to land. This visual join may well be initiated from an Initial Point which is effectively on the runway centreline, but at a speed/height where a 'straight in approach' could not be flown.