the lapped engines are much more user friendly and definitely faster

these pistons aren't as true as i think ! there are high and low spots in the machining and the lapping basically trues the piston and removes the high spots, this ensures an overall better seal then a traditional in car breakin....... I use 1500 AO grease in a specially made lapping die..........Another area is with piston damage, these high revving race engines can be prone to piston scuffing and removing the high spots on the piston dramatically reduces the occurrence of this happening .....

Also consider we repinch our engines these days, many guys believe the engines aren't at their prime til they have been repinched once....