Serious question, what's the benefit of a FF?
Well, it was a matter of focal length. A 28mm wide angle lens on a full frame camera would create an image at a focal length of 28mm. A 28mm wide angle lense on a crop body camera would create an image at the focal length of approximately 40mm. The differrence is that the latter image would no longer be wide angle and you would get less in the picture. In other words, crop body cameras did not produce good wide angle images.
What changed is that camera makers started to produce quality 10mm to 20mm wide angle zooms which even on a crop body camera produced wide angle images at 15mm to 30mm in focal length.
So the original advantage of FF cameras was better wide angle photos, but that is no longer the case. The advantage of crop body cameras is the ability to produce a telephoto shot with a lighter, less expensive lens.
So a 300mm telephoto on a FF camera produces an image at 300mm focal length. On a crop body camera you multiply the focal length of the lens by approximately 1.5 which means that a 300mm telephoto lens will produce an image at a focal length of 450mm which would be a much closer photo of the bird or subject in the distance.
Picture noise used to also be less of a problem on a FF camera, than on a crop body camera but that gap has narrowed considerably as well to the point of being unnoticeable.
skieur