It's not like it's better to use "static". You use static keyword when you want to call method or variable without creating class instantiation. In this example I just want to call method so I skipped creation of new Kata object. I suggest you read some about object oriented programmin, you will fully understand purpose of this keyword 😇 Anyway there is cool article about "static" keyword:
https://www.baeldung.com/java-static