> But the interesting question is: why did they write this article?
I'd guess because they're a part of the community and simply want to share their findings. I see no malice here. Having your work (whether writing or a new product) on the front page of HN for a couple hours is a great feeling and gives you a boost of motivation to continue your work.
They did mention the SEO benefits. Nevertheless, they are linking to a post on Indiehackers (not Simple Analytics website) which doesn't help them much in this scenario.
> Do they just think HN readers will forget about this article, and upvote their next bit of content marketing anyway?
As an HN reader, I come here more for comments than the articles themselves. If the article stirs an interesting debate on a topic that I'm interested in, I personally don't care if the authors used some "strategy" to get on the front page or not. Bad and uninteresting spammy content usually doesn't stay on the front page for long.