I didn’t see him promising that, where?
Either way, there are two big, and opposed, views of associating comments to the article, pl google it and you will find a very strong community of SEO “experts”(?) who argue against that. Because, your visitors would have to be super bright, super focused, super articulate – like you the article author – (but which they clearly are NOT), in order for your article’s SEO to benefit.
Frankly, even if articles are as “flat”, superfluous, and wrong English, as the comments almost anyone gets, then those articles won’t benefit from more of that kind of “language” (in the comments) either.
And conversely, if your articles are brilliant in all these regards, then comments spidered TOGETHER with them can only LOWER your SEO of those articles.
Common sense, isn’t it? Or, correct me where I go wrong?