Why is Body Biasing used in MOSFETs?

Body biasing is used to control the threshold voltage (Vth) of the MOSFET. When you apply bias to the body, you can either increase or decrease Vth. This helps you adjust the speed and leakage of the device depending on what you want.

From my side, I would say body biasing is useful because you can reduce leakage power in low-power designs. By applying reverse body bias, leakage current goes down, which is really helpful in portable devices.

We often use body biasing to improve performance. For example, forward body bias reduces the threshold voltage, so the MOSFET switches faster. But the drawback is that it increases leakage. So, you need to balance performance and power.