From the release notes, I can't see much new or changed functionality in Financials. Seems to be mainly a maintenance release for Financials. According to me, the most interesting changes are:

Record History
Record history is now available for Oracle Application Framework based pages. Record history allows a user to see data about a particular record, such as who created the record and when, and who most recently updated the record and when.

Reference Fields
Reference fields are now available for Oracle Application Framework based applications. A reference field is a web bean which participates in evaluating one or more properties of a flexfield, such as default segment value, value set, and context reference field for descriptive flexfields. Whenever the value in the reference web bean changes, the page is refreshed with changes to the corresponding flexfield properties.

Diagnostics Enhancements
Oracle E-Business Suite Diagnostics has been enhanced to offer a new user interface for managing and running your diagnostic tests. This new UI incorporates the User Management security model based on RBAC. In addition, the reporting engine is now integrated with Oracle XML Publisher.

Report Manager: Publishing to Multiple Worksheets
You can now use complex content sets with a combination of Page/Expand and Page/Total display types to publish reports. You can publish these reports to multiple worksheets in Microsoft Excel, or view the entire report data in the report display page using the ’ALL’ option in the expansion value list.

Payments: Multiple Divisions per Settlement Batch Enhancement
The Settlement batch process in Oracle Payments generates a number of files, based on system setup. Before 12.0.6, for large customers with multiple internal divisions, the number of files generated can exceed the daily limit set by third party payment processors, due to some limitations within Oracle Payments. In 12.0.6, the payment
system accounts with the same set of transmission configurations are being grouped in to a single settlement batch file which reduces the number of settlement batch files generated in a day.

Payments: SEPA Credit Transfer Initiation Messages
A SEPA Credit Transfer is a payment instrument for the execution of credit transfers in Euro between customer payment accounts located in SEPA. This enhancement creates SEPA Credit Transfer initiation messages for payments in SEPA, per the ISO 20022 framework and SEPA Credit Transfer Scheme implementation guidelines.