Also the wiz bulbs have one feature that most others don't have: they get their last state back after a power outage. If there's one thing you don't want, it's a full bright room after a brownout in the middle of the night!
The default is "Warm white, full brightness", probably mostly to avoid confused people sending back bulbs because they flipped the switch ON and the bulb remained dark. Since traditionally that meant a failed bulb.