The "pressurized accumulator" I'm referring to is just a water storage tank in the form of a bladder inside an air-pressurized steel vessel. A smaller version of the tank you find next to practically any well-pump to conserve pump cycling/wear and tear/smooth pressure spikes... Its participation in this system is wasting water, not conserving it.
It's included from the factory just so nobody has to wait for filtered water to pass the membrane at time of use, instead experiencing an instant powerful jet of water out of the filtered water faucet.
Installed with a standard hydraulic shut off valve (ASO) you won't see any issues but you won't get much in the way of improved storage pressure. You will just see improved product/waste ratio as the pump negates the back pressure from the tank. The downsides are the periodic thumping noise and the added complexity of the extra tubings and fittings.
Installed without an ASO valve the permeate pumps will cause some TDS creep and bleed high TDS product water into the storage tank each time the system stops and starts. This will mix with the low TDS product water and raise the average up somewhat. The amount will vary on usage behavior but it's a noticeable TDS bump for most users.
Anyone with an RO system living in a water-scarce region should install one! It'll save you many gallons a day, and has no downsides, unlike most other water reduction devices (like weak-flushing toilets or barely-misting shower heads).