They are there to match the characteristic impedance of the cable to the load.
Without them reflections occur.
This distorts the signal.
With a square wave that appears as ringing which can cause clocking errors.
Eg a video cable with an impedence of 50 ohms should be terminated with 50 ohms.
Likewise an audio cable is normally terminated with 600 ohms.
Pixel to pixel distance is so short to make them unnecessary between pixels.