People working on a product spend a lot of time thinking about the challenges and issues related to it. They are well equipped to write about these problems because of that hard work. If they also include something self-promotional in the piece, it doesn't diminish the value of the other points they make. And I'd say if they've taken the time to write and share their specialized knowledge (which you find interesting), it's not unreasonable to also include a message promoting a relevant product.