If there is traffic, that means that your spot behind the cyclist will immediately be replaced by another car. If everyone acts like that, the biker caries a bubble of faster-than-average cars with them. Hardly ideal.

I propose a different protocol: Slow down, and follow the cyclist until the situation allows to safely overtake the cyclist at a nice distance without speeding up too much. You will still travel faster than the cyclist, and you have actively contributed to the safety of the cyclist.