The lowest input to output voltage drop you can get with a standard bridge rectifier is nearly a volt through the 2 conducting diodes for each half cycle, even with Schottky diodes in the bridge.
That can generate a dissipation of about a watt per amp of output current in the bridge diodes.
A MOSFET bridge circuit has a very low voltage drop, as determined by the ON resistance of the selected MOSFETs, thus it can be less than a 100 millivolts for common, low on-resistance MOSFETs, even for...