Winning races usually requires sprinting ability. If you’re racing a bike, as an amateur or professional, becoming a better sprinter can be the difference between 1st place or the 20th. So it’s crucial to learn how to sprint.
You can say “I am not a racer, why to work on my sprint?” Because sprinting is fun. It is pure play to go fast. Also, the ability to sprint is useful in emergencies, like evading a car that is coming at you from a side street or outrunning a chasing dog.