The use of capacitive decoupling is the main method to solve the problem of power supply noise. This method is very effective for improving the response speed of transient current and reducing the impedance of the power distribution system.
For capacitive decoupling, some are explained from the perspective of local charge storage (that is, energy storage), some are explained from the perspective of impedance of the power distribution system, and some materials are more confusing. It will raise resistance, so many people feel a little confused when looking at the information. In fact, these two formulations are essentially the same, but the perspective of looking at the problem is different.