Because it is a big claim. And there are many different kinds of photographs you can take in many different situations, so something what is an advantage in one situation is a disadvantage in another.
Computational photography can overcome some of the optical limitations of the small sensor. E.g. you need a really good camera to get the dynamic range that is available with iPhone HDR.
Old camera (I am not aware of any modern cameras having 6mpx sensors) is an old camera. Cheap glass is a cheap glass. The bigger the sensor the better your lens has to be optically, because light is bent at the bigger angles.
The two most obvious areas (ergonomics and interchangeable lenses aside) of advantages of the "proper" cameras with bigger sensors are low-light performance and "bokeh". Otoh, if you want to have as much in focus as possible small sensors win.
No. No matter if you have wide-angle lens or the telephoto lens, you still need to cover the whole sensor with the image and the distance from the last glass element of the lens to the focal plane does not differ that much.
Computational photography can overcome some of the optical limitations of the small sensor. E.g. you need a really good camera to get the dynamic range that is available with iPhone HDR.
Old camera (I am not aware of any modern cameras having 6mpx sensors) is an old camera. Cheap glass is a cheap glass. The bigger the sensor the better your lens has to be optically, because light is bent at the bigger angles.
The two most obvious areas (ergonomics and interchangeable lenses aside) of advantages of the "proper" cameras with bigger sensors are low-light performance and "bokeh". Otoh, if you want to have as much in focus as possible small sensors win.