They go together and are best in balance, like ABV and hops.  Deep powder reduces scary steep slopes into aim and go floating surreal experiences.  This is a rare gift in the mid Atlantic.  

Too deep without enough pitch and you may find yourself unable to move downhill even pointed down the fall line.  The most common causes of falling in deep powder are flat light and failure to accept that speed is your friend.  That and patience; guide your turns, dont crank them.  Ski centered and two footed.

Off piste in deep powder I wear a whistle on a lanyard, and a small pack.  If I fall, i take the pack off, lay it on the snow on my uphill side and use it as an aid to getting up.  Works a lot better than the traditional crossed poles.