Hi Rebecca - It depends on your scenario.
if it is just processing a file and calling the ABAP proxy to load that data then you might not need BRM..
though i'vent worked BRM, If you have any workflow /maintain some business rules in processing that files, then you may use it.
Process Orchestration is just a package which has PI + BPM and BRM.. and each product can be used independently based on your needs.
Go through the below document to understand more on BRM -
Overview of Business Rules Management Technologies at SAP
case study -