SuperRAW and HDR are easy to confuse because both processes capture and merge a set of images in quick succession, but they exist for two completely different reasons.
HDR is used in situations when you are shooting a scene with a wide dynamic range. An HDR image is composed of multiple pictures taken at different levels of exposure and then combined to create a more balanced image. Each exposure captures part of the full tonal range and then software combines them all into a single image.
On the other hand, SuperRAW is designed specifically for extreme low-light photography. A SuperRAW file is composed of multiple pictures taken at the same exposure, and later combined to create an image with a much lower level of visual noise. This file can be processed through DxO Software just like any standard RAW file, but with added advanced temporal noise reduction. The advantages of SuperRAW are most apparent when denoising a high ISO image.