In essence, satellites and other spacecraft are just computers in orbit, with their processing power limited by the amount of available electrical power. Either increasing the processing electrical efficiency or simply increasing the electrical power will therefore free up more processing power available within the spacecraft. This can have major consequences in spacecraft and mission design.
Some examples of the impact can be illustrated with the case of an Earth observation satellite. In many cases, the main instrument may require more power than is able to be generated. This is especially the case in active instruments such as radar systems. Because of this the instrument has to be operated in bursts. With more overall power available, the instrument can be operated for longer bursts or just more bursts overall.
With more processing power available, more processing of sensor or instrument payload data can be performed on board. Combining optical bands in images and performing compression may reduce the amount of data that has to be downlinked. This also makes it possible to operate the instrument longer or more often. It also may reduce response times when wanting to act on the data.
Staying with the downlink, having more electrical power available can increase the availability of the link and increase the link's bandwidth. This again can increase the usability of the instrument or increase the availability of the entire spacecraft. In the case of telecommunication satellites, this will also increase their availability and throughput.