My personal opinion is that DPN's are sort of a tool of the trade for knitters, and therefore, it's probably a good idea to learn how to use them.
However, I really don't care for them too much, and do my socks on 2 circs. But I did do a few small projects on dpns just so I know how.
Still...it's all a matter of personal preference and what works best for you. Some folks swear by dpns, some by circulars, and now more and more love Magic Loop---so I say, go with what works and what you enjoy.