a few bullet points:

• newbies start off with a low reputation and steem value. So before taking time publishing posts with fantastic content, which then are overlooked easily (he is a newbie after all), it is easier to first get a higher reputation score by commenting on posts first
• Gay Vaynerchuck (an overrated social media guru) is correct about "jab, jab, right hook": First you need to engage with your audience and give - then later you convert it into money.
• From a monetary perspective commenting makes more sense than publishing actual content from my short experience here. Not sure if this is the best approach as a user, nor for this platform, but this has been my experience here so far unfortunately. I think this should be improved on by the developers.
• Commenting can be a lot of fun, and one should try to be genuine. If I write a long post I want it to receive a response by users. And in the best scenario it would actually lead to a discussion with converging view points, rather than simply "great post, follow me".