Doesn't do any damage-you're merely resetting the adaptive throttle response. Your car "learns" how you drive and adapts. If you've done a lot of in-town driving, the response gets set to less responsive (you're only giving it a little gas and you're doing a lot of idling). The reset only affects throttle response, but since it's almost always quicker after reset, you have be ready for it shifting gears. If you're always driving in the same place, though, it's not really worth it. Those of us who do a lot of "mixed" driving, the in-town stuff can bog them down.
2007 3.0si coupe, sapphire black, saddle brown extended leather, heated M seats, premium package, sport package, Carver, light poplar wood trim, xenon, headlight washers, 6 spd. Member BMWCCA, ZSCCA, Homecoming 08 Pirate.