I actually use this trick alot whenever I use marth or lucina (although I feel like it works better for lucina since it's hard to space it for a tipper, and it's consistency depends on character weight and fall speed). I've also tested it extensively versus alot of characters with a friend of mine, I feel like it's guaranteed on alot of the cast at certain percents, and at the right percents, it's hard to escape for those who can get out of it. I have been able to pull it off on fox.
It's also better to go with F smash instead of U smash most of the time since it comes out faster, can KO earlier than U smash if you're close to the edge, and if you space the dancing blade hit just right, and retreat ever so slightly with it after it comes out, you can sometimes land a tipper (results for this has been inconsistent for me, tippers can happen if you space it a bit, but they won't always happen).
I also like how you you considered it as a form of edge guarding, I never thought to use it that way, I'm eager to go practice that now.
