Integration and analysis of the data from other sources - key selling point in CognitiveSEO for me is how visual is the data and how you can go from diagrams/trees/charts to raw data. Disavow generator is really nice, competition comparison too. Also they've just added content analysis tool which kicks ass! I can throw away few other tools and use only this one for most of my SEO needs.
Nowadays there are a lot of large tools, integrating a lot of features that everyday SEO expert needs - you're probably aware of MajesticSEO, Ahrefs, Moz, etc. but Cognitive is one, that gives you access to all this data and more, and i have a feeling, that it's a bit underrated by s SEO community. If you're looking for SEO tool, that works FAST, is reliable, supports many countries and will analyse data for you - give it a try.
Did i mention API? You can access the data programatically and add Cognitive to your automation workflow - which could be very useful and save you money on integrating the data yourself.
Could use a bit of onboarding experience - i can imagine that it's pretty hard for new users to use this tool - when you're SEO pro, you'll know what to look for, but for business owner, i think it has a little bit to steep learning curve.