I initially thought BAPIs were categorized as an interface, however, after reading about BDC on the scn wiki, I learned that BAPIs should be used over BDC when bringing in data whenever possible.
"BDC was a great way of uploading data into SAP in a pre-BAPI era, now SAP is making available BAPIs for most of the functionalities, someone should first look out for BAPI if it is not available then go for BDC."
So, does this classify BAPIs as both an interface and a conversion tool in RICEF?