In a boost converter, the inductor is necessary to achieve a higher voltage on the output than the input. I was thinking about a buck converter and I realized I don't understand why an inductor is necessary to step down the voltage. It seems it'd be much simpler to just have a capacitor bank at the output and a switching transistor that keeps the capacitors at the desired voltage using a feedback loop. I threw one like that together in a SPICE model with a periodic load and it seemed to work just fine. What's the advantage to the inductor in the circuit? Is it an efficiency thing?