But the basics are the same: the capacitor acts as one leg in a voltage divider, followed by some rectification and regulation, with the load as the other leg. Why the complete isolation?

some voltage dividers and voltage references have low values of zero, offset or residual impedance resistance, inductance or capacitance. Others can provide a precise and continuously variable value ...

voltage divider, or component has a computer interface option for programming, control, or data acquisition. Variable (Continuously) The standard or reference can provide a precise and continuously ...