I use a steady to help drivers with their depth perception (I know that I have a hard time telling how far away a bicyclist is with flasher only) and a flasher to get attention. I was convinced of a flasher when I saw one over a mile away on a 6 lane road. A auto pulling out from sidestreet should see it fine.

Also, helmet steady can be moved towards an auto pulling out if need be.

BTW - tests on water resues have shown that flashers get attention, but once close rescuers have a hard time finding the person to be rescued and need a steady light to do so.