It's not useless, although better self-defence systems exist.
Generally speaking, most combat sports aren't ideal for self-defence because they have restrictions on where and how to strike, as well as they tend to focus on not ending the fight immediately.
Self-defence ideally should focus much more on ending fights as quickly as possible.
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The Party told you to reject the evidence of your eyes and ears. It was their final, most essential command.
If you're not careful, the newspapers will have you hating the people who are being oppressed, and loving the people who are doing the oppressing. —Malcolm X
If you feel useless, just remember the USA took four presidents, thousands of lives, trillions of dollars and 20 years to replace the Taliban with the Taliban.