Do you honestly think that every article posted on a product's blog should include a disclaimer that the post may contain information highlighting the usefulness of their product?
To be fair, it seems from the article that it's their interactions with the community using the feature that shits on it. Or do you have specific counterpoints to their arguments made against tiered storage in kafka? As far as I can tell there are two points being made against tiered storage: operational burden is increased and networking costs (which if you've read any of their other posts or visited their homepage, is a primary motivation for the existence of their product) are not reduced.
