A curve is useful when it changes how you enter a room, not when it ornaments a photograph.
Soft geometry returns whenever people tire of being told where to stop. A rectangular opening is an instruction. An arch is a release. Neither is automatically better. The question is whether the curve is doing structural or circulatory work, or whether it is a motif applied to a flat idea.
A curve that does not change the route is only a drawing.
Light prefers a radius
Daylight moves more kindly around a reveal that is not a knife-edge. Shadow pools in a soffit. The body reads the opening as thicker, more like a building and less like a partition.
Closing thought
Use a curve where a body turns, where light needs a place to slow, where a wall should feel like it was opened rather than cut. Leave it out where a straight line is already telling the truth.
Geometry is hospitality at the scale of the shoulder.
