There is one usage case, i can call - reversing recorded piano and some other
instruments. One case, when sequencer and even instrument settings are not
last step before mastering. I'm not expert and at all badly aware of existing
music to mention examples, but i know at least one - in Black Mesa game - some
soundtracks, marked as "mesa remix". I don't see it bad to mention such stuff
there, since it is done completely by fans, no matter with what resources and
software.

Additionally, in gui clips may display inline status, with indicators for
direction and all other clip-individual info, such as speed (probably, that's
all - don't know, what other indicators are good to have there).