I only use it when I have passengers in the car. It will definitely give them a smoother ride, although to the driver it's like driving a sofa bed. Someone else on here mentioned the jerky effect of the untempered ordinary D mode on the passengers, the driver has a steering wheel; passengers can get thrown about and if susceptible can soon feel quite nauseous.
As a taxi driver school trainer in Perth (amongst other things), this was one of the primary skills I used to attempt to impart to my pupils. One day I had 4 of the assorted Somalis, Indians, Brits, Kiwis and Aussies attending the class in my training car and the first Somali got into the driving seat; before we had travelled 100 mtrs approaching a school crossing he was already doing 80kms in a 25km zone.
I used to despair for the poor passengers they were going to carry in the future.