Additionally it should be mentioned how crazy imaging tech got lately. USB2 with 480 mbit/s is at the physical limit near the speed of light. This is why it easily fails in reality if you have the slightest disturbance. Faster busses like USB3 basically use more lines even if we still call it serial...

If you would transfer raw image data (rgba) you get what for full hd images? Around 7 fps? I don't even want to see the bus for modern smartphone cameras that now seem to casually have around 100 megapixels...

So very fast "on-site" encoding is pretty much mandatory today...