Simple Finance is SAP FICO on HANA.
Yes it is the future but HANA is a database and doesn't work alone, it needs R/3 to get its data as well as third party software.
However a lot has been changed with S/4 HANA with some totals tables being removed, no period end closing etc.
Yes indeed Simple Finance and Fiori is the future. It will be interesting for you to venture into it but like everyone on this thread, I will say the same.
Grab the fundamental concepts of ECC 6.0 first.It is a vital base for you to understand the functionalities of Simple Finance.