Energybrite is an Oxidiser as is Oxybrite.
Oxidisers add Oxygen to a stain
Reducing agents Such as Spray and Go, most coffee stain removers etc, remove Oxygen from the stain.
Both these processes are designed to alter the Chromophore. The Chromophore is what gives the stain its colour.
The object is to alter this so that the stain becomes colourless. Even though you can no longer see it, it may still show up under Ultra Violet light.
You would mainly use reducing agents on any stain caused by something you eat or drink.
Oxidisers are good on other coloured stains such as water stains, browning etc.
Oxidisers are also very good when used as a booster to other cleaning products. The release of Oxygen helps release dirt from the fibres. It has the additional benefit of being naturally anti bacterial, virucidal and anti fungal.