That said, we do offer more than just information. We allow users to track their sleep on our app so we can customize our program. Each user goes through a personalized track based on their sleep habits. We also automatically calculate your sleep restriction window for you. We also have relaxation content that you can listen to right before you go to bed, a worry/ gratitude journal and a routine tracker.
Books by (relatively) renowned/trustworthy experts are also a thing and they all cost less than your monthly subscription.
+ A lot of people don't have the time or patience to invest several hours into reading a book. They'd prefer things broken down into actionable steps. In fact, we've done a lot of product testing to figure out how to improve program efficacy and we found out that the shorter and more "bite-sized" we made our modules, the more willing our users were to follow them, and the better their result.
+ The big "open secret" in the sleep research community is that yes, CBT for insomnia is a great starting point, but it needs to be followed up with further psychology-based care. Stellar Sleep delivers CBT for insomnia-based programming initially, then transitions into continued psychology-based programming which sustains the results of the initial CBT for insomnia work.
Much of the content is (and ought to be) freely available information anyway, at least for boilerplate CBT-i (see e.g. https://insomniasos.net/). Obfuscating what is the size of a buzzfeed article behind payments and apps to make a buck is absurd.
Seeing a professional is one option, but ymmv. GPs don't seem to know much about this and reflexively prescribe pills because that's what people want and expect of them. Sleep specialists can be good, but the source material behind their approach can be limited and dated (like CBT-i itself). What I did is read a pile of research articles (maniacally at first), and books. It's not for everyone, but you'll find more useful information than in glorified advertisements in google searches.