What do you think of the oversimplified myth 'CO2 is plant food'?

Our boy Dawei got his first Skeptical Science post published, really tearing apart the myth that more CO2 is necessarily better for plant growth.
http://www.skepticalscience.com/co2-is-p...

What do you think of the myth after reading the post?
Update: Fair enough, I should have said "oversimplified argument", not myth.
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