How would you show a photographed image as a svg? Either you would have to "vectorize" the image which would look totally different or you'd create a grid of vectors with different hue values, ultimately representing pixels in an extremely inefficient format.

Raster graphics and vector graphics can't be compared because sure, you could create 2 million vector squares with individual positions, sizes and colors and align it into a 16:9 grid or you could just use a jpg. The latter being a fraction of the size and processing power needed to display it.