because setting a greeting recording to a stream file isn't used any longer - it was necessary back when greetings and voice names had to be uploaded via CUALs (SOAP interface) even if using REST for your admin functionality - CUALs would generate a stream file for you and pass the Id back and you would then take that and use it for a greeting, voice name or interview handler question or the like - since the REST path does the direct WAV handling now it hasn't been necessary in some time.
Older tools that still use CUALs (COBRAS does this since it has to work on older versions of Connection) it used string there (back before we added enums in for clarity) - I could add an overload to take either method...
