You're tying your wagon to a less-than-healthy horse for no real benefit that I can see?
Also, FFmpeg in general clashes with the unix philosophy, and makes it harder to get what you need done.
If it was a standalone decoder, I could pipe the output PCM into any encoder I wanted, but now I either have to deal with what ffmpeg provides, OR output to a wave file on disk.
But hey, whateve. I've learned a TON about programming my projects, BitIO, etc, so it's not a huge deal.