Clojure is my favorite JVM language, too (alongside Kotlin), but I think Groovy can fill a different role even if your go-to language is Clojure. Groovy is great for writing non-lispy DSLs; one of those is Gradle, that's quickly becoming the de-facto standard JVM build tool, slowly but surely replacing Maven. Also, I think Clojure is better for "serious" projects, while Groovy is better for throwaway scripts (not that you can't do serious projects in Groovy or "non-serious" ones in Clojure).