I do agree that when you're trying to write expressively then "correct" is by no means the same as "right" - and right should always win.
On the other hand, I see endless, endless essays - perhaps the majority - where they don't use enough of them to articulate the meaning of what they're trying to say. Commas are about units of meaning with the sentence, and they matter so much.
I actually had one student who said that she used to use commas a lot, but saw others not using them and thought she was being "old-fashioned", and so tried to train herself out of it.
As soon as I got her to read her sentences aloud, of course, her brain had to make sense out of the sentence in order to speak it - to understand the units of meaning - and so she could feel where they ought to go.
And I see it in creative writing too: students leave out commas where they should put them in quite as often as they put them in where they're either incorrect or wrong.
A brilliant quote I've read just this morning, in a photography magazine: the photographer's talking about straightening horizons being one of those things that you need to do even though most viewers wouldn't be aware of the un-straightness in the orgiinal, and he quotes his English-teacher partner's wife: getting the commas wrong is like not dusting the room and people may not notice the dust, but the whole room seems muted and unkempt.
<Added>I had one CW student who said he used short sentences in order to avoid using commas because "they're old-fashioned".
I nearly wept.
And yes, his prose was every bit as pedestrian and impoverished as you'd expect.
<Added>And yes, I have blogged about it
http://emmadarwin.typepad.com/thisitchofwriting/2012/06/commas.html