The reasons are for increased fuel pump lubricity, water absorption/separation, keeping injectors clean and prevent fuel gelling in winter. There are more things it does but those are my major reasons. Being using this stuff since diesel fuels switched to low Sulphur diesels and our cold winters in Alberta. Plus with the in-bed fuel tank, it kept the diesel fresh and protected the tank. Used it in the Duramax since 2005(?) and never looked back!
My nickels worth (we don't have pennies anymore in Canada)
2016 Platinum Reserve 2 tone blue
BAK MX4 tonneau cover
stanadyne performance formula
2015 Wind River 250RDSW
2017 370Z Sport Touring auto