The performance of the JVM is phenomenally good with any modern implementation. The only issue remaining is the relatively poor loading time of the JVM. Hence, short tasks/scripts make little sense to run because the overhead of the startup overshadows the performance of the JVM.

But for long-running applications, the performance is very good, and the time it takes to load doesn't really matter. The startup time mostly effects the programmer, who has to start it up to debug the system so often. Clojure sort of mitigates this by having a REPL where you can do testing/debugging without restarting the JVM every time.