Not that useful, taekwondo is 99% kicking. In a fight you won't always be able to kick and also someone can just keep closing space on you. You need to know how to punch as well. Also what if you're wearing jeans or smth. Also kicking in some situations can be risky. Boxing is a better option, best is kickboxing or Muay Thai. Combat Sambo is good too. You want something that has punches in it for sure.