I think you are right. Years ago I put a diffusion surface (white plexiglass) in my condenser head and could not tell it from my coldlight. Diffusion means you are scattering the light to the maximum degree --- that light strikes the negative from ALL angles. Condensed light strikes the negative at one angle --- orthogonal to the surface. In truth, coldlights, condensers, diffusers, point lights are all in the middle to varying degrees. The above relates only to the optical properties.

The nice thing about a coldlight is that it is very diffuse and at the same time small, efficient, and generates little heat, which can be a real problem. If you have a good diffusion head or color head, you don't need a coldlight if you are not having heat or space problems.