It can be very useful for when your in the saddle jumping that horse and can help them with proper muscle development! So I think it's great!
It's ok. Just make sure the horse has plenty of room and on a long rope.
It is a great tool. Just ensure your lunge line doesn't get caught on the jump
I think it's a great tool to use too
I think it's a great tool to teach horses how to jump properly without a rider getting in the way when done correctly. I wouldn't jump them very high on a lunge line due to the fact they won't have much preparation for it on a circle but I think it's a great way for young horses to figure it out before you jump them under saddle.