Unless you have a telescope with an extremely wide aperture, then no this sensor doesn't help. Pixels that small mean it is diffraction-limited if the telescope

Unless you have a telescope with an extremely wide aperture, then no this sensor doesn't help. Pixels that small mean it is diffraction-limited if the telescope has an aperture of F/1.0. That's plausible in the most funky of camera lenses (but expensive), but completely unheard of in telescopes. The widest aperture telescopes are the RASA-type which have an aperture of around F/2.0, and they are expensive enough. They are regarded as fantastic light-sucking monsters, great for dim targets but not for small targets. Most of the time, the image sensor on a telescope actually slightly over-samples the sharpness of the image that the telescope is able to project. So having smaller pixels won't help. But to actually answer your question, these small pixels will be worse at low-light applications than larger pixels.