Contour is actually a product of Comcast. It's the Comcast X1 platform and Cox signed a licensing deal to rebrand it as Contour 2. If X1 has an app, Contour could also have the app...it just depends what was in the deal.
Cox not using the app may be an issue with service support. If there is a technical glitch, Cox might not be able to tinker with its coding to fix it. To resolve a glitch, Cox would have to pay Comcast to fix it. Cox is just saving some heartache and cash by not using the app.