The SMP HANA cloud has the same look and feel as SMP 3 cockpit. And you are right the Odata REST APIs can be used here to develop apps and that's what makes it similar with SMP 3 . So as a learner anyone can start with the SMP cloud trial similar (it has the admin console).
When we are looking at SMP 3's new features, kapsel is not only the one which is making the difference. IG (Integrated Gateway) too makes SMP 3 new to the developers. It has a separate cockpit itself to manage the Odata services and a developer tool GWPA from SAP, which involves writing code in Java.
Midhun VP