HANA is able to run transactions and analytics on a single, in-memory column store, Hank. It does not require a separate transactional RDBMS at all. S4 has been designed with this kind of architecture in mind, so, only runs on HANA, on-premise, or in the cloud.
For the current generation of Suite applications, customers typically mix and match ASE and HANA depending on their requirements or landscapes.