I think it has decent applications in that it basically allows you to shoot high durability projectiles at your opponent at your leisure until they run out. Instead of just teleporting forward and burning them all for minimum damage/chip very fast. Nothing except projectile supers (and only certain ones at that) will beat the durability of the swords so I think it will have some interesting applications in the future.
Crown swords is a great mix up tool if you activated spiral swords for mix up, are almost out of time and have the meter to use.