Dear Thevendran,
simple finance now is just renamed to S/4 HANA FINANCE. This is an exchange add on that is to bring to ECC 6.0 and there are some prerequisites: SAP ECC 6.0 Ehp 7, Fiori, and so on. Yes, S/4 hana finance by the exchange add on will subtitute the ERP Financials (new processes, new functions). The main change is that the System will use the new table ACDOCA (accounting document actual) that contains all the FI, CO,FI-AA, and so on details) and many FI index/total tables will not exist anymore (BSIS, BSID, and so on).
Ciao and have a nice day.
Maurizio