There's some truth there, but if you send an email to the East Coast US at 2am, there's going to be a small chance people will read it when they wake up (they'll already have tons of other stuff competing at the top). Same goes with Twitter. You can't tweet something for everyone to see at a time when your target audience is not watching twitter. You need to test for that.

Either way, the essence of your argument is correct. Useful content fares better that fluff.