I was able to convert a couple of my data scientist colleagues over to using Scala (given that they were writing code for our Spark cluster it seemed like a no-brainer compared to Python or R). It's not thousands of times faster but it might be ten or a hundred times faster, and a lot of the time you can write the very same code aside from punctuation (and even that difference is smaller in Scala 3, although I don't think Spark has moved to that yet).