The Google Pixel phone lacks an optical image stabilization (OIS). It only features a digital image stabilization which is very useful when recording videos. Most of the premium smartphones on the market and the Google Pixel direct competitors, like the Samsung Galaxy S7, iPhone 7 Plus, LG G5 - all have an optical image stabilization.
Considering the fact that the Google Pixel camera is one of its main selling points due to its proven performance, we are just left with one question: why Google didn't bother adding an optical image stabilization? which could improve the camera's low-light performance and reduce the occurrence of image blur for both stills and video recording.
It might be that Google believes that there is not need for it. The digital image stabilization works amazingly well for videos, and therefore makes OIS less of a necessity and for stills, the large sensor pixels, and the fast f/2.0 aperture lens should satisfy most people's needs for low-light photography.
Google Pixel costs almost like the iPhone 7, so it makes you wonder why not adding this feature, as it can improve the low-light performance even further, allowing the camera to shoot at slower shutter speeds under the recommended by the shutter speed rule of thumb (1/focal length of the lens), and be able to achieve a sharp well-exposed image.
I have no idea how much an optical image stabilization module costs, but I don't think that it would have made the Google Pixel phone much more expensive, after all, its competitors did implement this feature, and I think that the Google Pixel camera can certainly benefit from it.
I see that as a disadvantage, and I hope Google will opt to add this feature in the next iteration its Google Pixel phones.