A:Answer (the soft roller you asked about) is designed specifically for hard floors — it has a soft nylon and carbon-fiber filament roller that excels at picking up fine dust, debris, and hair from smooth, hard surfaces without scratching them. On those floors it’s gentle and efficient, and that’s exactly what it’s for.
But here’s the catch: Dyson’s fluffy/soft roller heads are not made for carpets or rugs, even delicate ones. However it's pretty consistent that the soft roller isn’t effective at all on carpets and area rugs — it simply can’t grip the fibers to pull dirt and hair out on a surface that has pile. It won’t damage them by itself, but it also won’t actually clean them well.