Burst mode is applying only whole cycles of power to the load. There is no phase control. It is a ZVC technique, so there is no noise either. Only when you need high speed control and high resolution/low ripple requirements do you need to invoke phase control: We made a furnace controller to control 800C +/-0.1 C and heat up/ cool down rates from 0.2 deg C /min to 100 deg C /min. That needed phase control !

Steve