GearTronic--Use it or just for wannabe Racers?

[kerldc1]

'06 S60 2.5T automatic trans w/ GearTronic. We just noticed there's no usual P-R-N-D-L, so we figured we're supposed to pop the shifter into the GearTronic manual mode for engine braking assist on steep hill descent? We are very light-footed with this car, as it's new to us (open road mileage easily 30.5-31mpg average) so we have no need to zip around town and jackrabbit at signal lights. Who's actually using their GearTronic daily? Is it worth using? How often? Just for downhill braking? Your advice?