The purpose of the reverse osmosis booster pump is to increase water pressure going into the RO unit.
Reverse osmosis is a pressure-driven process.
RO units run well on typical city water pressure of 60 psi, but they run even better with a pump to boost the pressure to 80 psi or higher. The booster pump assures that the water at the input of the reverse osmosis membrane is enough high.
The benefits are: