[MelindaV]

the jack pads add height - so more important when the car is on a flat lift than using a single point jack. but for either, having the nubby in the hole keeps it from moving.

(coming from someone who's one previous car with recessed jack points ½" above the rocker panels, was flat lifted by a dealership service guy and added 4 dents to the rocker panels and messed up the panel alignment all around, and another previous car with aftermarket ground effects crushed by a tire shop for using a flat lift without blocks).