I think that striking the balance is the difficult part. I agree on both accounts that the most important affirmation in writing poetry is human response rather than publishing credits. For me, a friend, stranger or family members enjoyment of poem has a longer lasting effect than seeing it published in a book.
We write poetry for people to read do we not, and there in lies the conundrum. Submitting to magazines and journals increases your level of readership and brings your poems to the masses so to speak. Personally, I also submit to places as a form of motivation. It's a way of measuring and encouraging myself to continue writing. I hold my hands up and agree that they may not be the best reason, but belief rejection has as big an impact (if not more) on my hunger to write than acceptance does.
I think that Hippasus has a point when he says that although publication credits aren't everything when you go to submit a manuscript or self-publish people will invariably make judgements based on credits. An interesting thing I noticed was that when Alan Gillis published his first collection Somebody, Somewhere none of the poem had been previously published. A rare step for a modern poet.