Im using it. Because i get from ffmpeg working Windows builds with libass. And under the sheets i need only the libass video filter, x264 as encoder and sometimes an aac encoder.
The question should be who still uses ffmpeg? Maybe the win builds of vlc or the integrated ffmpeg in xbmc, but most others use libav.
I seriously doubt this, from the top of my head I can think of blender, vlc, mpd, amarok, gegl, xine, k3b, vtk, which uses ffmpeg, which software depends on libav?
The question should be who still uses ffmpeg? Maybe the win builds of vlc or the integrated ffmpeg in xbmc, but most others use libav.
VLC has a copy of ffmpeg and only ffmpeg (not libav) in its repository. VLC uses ffmpeg on every platform by default. You and your niche distro may do it differently but no one else cares and uses ffmpeg.