Spoilers

It doesn't say cast without paying mana costs so I basically read it as "end as many fights you want if you're OK with recasting your creatures this turn or losing them."

Helpful if your opponent benefits from the fight itself, like a creature that adds a +1/+1 counter every time they kill a creature.

Also great for ETB/LTB triggers. Any time you'd like to return a creature to your hand to play again, this is probably great. Since you wanna return it anyway, you get to deal free damage if your opponent doesn't wanna let you redo an ETB trigger. Feels like a combat Ward in that sense. Your opponent pays the creature's Power in order to prevent an extra ETB trigger.

But you do get to pay for each time you do this, so I doubt It'll let you run away with anything, just get you an extra trigger or a few extra points of damage.

Could pair with ninjutsu as a fallback. If blocked, exile it, replay it, get any ETB/LTB triggers. If not blocked, Ninjutsu it, do the usual ninja things, replay it, get the ETB/LTB triggers, too. Doesn't work as well on the ninjas themselves though, they usually cost more to play normally, so exile/replay is costly and might be beyond your mana.