It appears from below SAP slide (though stated as Labs preview) that EWM will be embedded in digital core of S4H in On-premise edition of 1610 release i.e functionalities of EWM will be made available in digital core and there is no need for running EWM as a separate application.
Advantages will be
Master data and transaction data need not be transferred between the systems and CIF is not needed (Reducing TCO , inconsistency and downtime of systems)
Material master , business partners stored only in one system (thus reducing the data footprint )
Customizing objects like HU types need not be transferred to EWM (thus reducing data footprint , inconsistency and complexity of the systems)
There will be no duplication of business documents ( Presently ECC delivery document are replicated as separate document numbers , thus reducing data redundancy and time spent in matching the documents numbers in reports etc)
Common maintenance / down time
Now , the question is whether this native integration of EWM with S4H will be relevant / beneficial for all customers or scenarios ? Answer is NOT as
One of the main USP of SAP EWM is its capability to operate in decentralized mode i.e both ERP (ECC or S4H) and EWM can run independent of each other i.e all Goods receipt (GR) , Goods issue (GI) and other warehouse activities like VAS etc can be performed in EWM even if the connection with ERP (ECC) is broken. All these transactions / documents get transferred / updated to ECC once the connection is restored.
So, the stand alone deployment of EWM will continue for
Business critical warehouse operations
Risk mitigation (during migration to S4H etc)
Scalability for large warehouses
Hence, if the warehouse operations are de-centralized, then it needs to be ascertained whether the option of native integration of EWM with S4H core should be chosen or not.