I WONDER - Why Do Kangaroos Box?

Male kangaroos are known for their boxing skills, which they use to establish dominance and compete for female attention during mating season. They balance on their hind legs and use their front legs to deliver quick jabs, with their tails providing support. These matches are usually not harmful and help determine the hierarchy within the mob.

In what ways are boxing matches among kangaroos usually not harmful?

What is the significance of boxing matches among male kangaroos within their group?