Ok, definitely not a "free" disengage per se. It may be a little more niche than the Defensive flourish, but still way more useful than Slashing.
I think I'm just trying to further justify/magnify the Swords Bard in my head as I really want to try it out.
But I want to add that I enjoyed this...
I have to disagree with the assessment of the Mobile Flourish because it pushes them "up to" 5 ft _plus_ the number rolled on the die. So basically, it's added damage and disengage. So you hit them and do more damage and get free no-save pushing that allows for a disengage. If you like you can...