If you would like to try something that's closest to Scheme and has access to the rich libraries in both the Python and Java ecosystems, give Clojure a try. You have access to the Java libraries out of the box and, with libpython-clj [1], you get access to your familiar Python libraries.
As to what you get going to Scala, it depends what matters to you.
Does 50x faster compute matter to you, for the code that’s CPU bottlenecked but inconvenient to rewrite in C?
How about easy parallelism, to trivially and fully utilize multiple cores without clunky subprocess management?
How about easy packaging? One builtin command to package your program as a single file that can run anywhere with a JVM, no other global installs required?
You do give up some things using Scala: compile times are slower than iterating on Python scripts, the JVM runtime takes a second or two to warm up when launched, and you don’t have quite the same numpy/scipy machine-learning ecosystem. Whether that is worth it is up to you!