Composite HDR shots are supposed to be done such that the shutter at the fastest speed properly exposes the highlights and the slowest speed completely blows out on the highlights, but the extremely dark shadows are properly exposed. In other words, it's about filling in the details when overexposure causes amplitude clipping.

How most people end up shooting HDR, however, the component images mostly all have full detail in the shadows and highlights, meaning the final image really not much more than you've described. You can do that with a single shot and a contrast slider.