SparkMLib - the machine learning library - has only fewer ML algorithms, but they are ideal for big data processing. Scala lacks good visualisation and local data transformations. Scala is definitely the best choice for Spark Streaming feature because Python Spark support is not advanced and mature like Scala, 2 days ago. You can use Scala' s basic programming features with the IntelliJ IDE and get useful features like type hints and compile-time checks for free.
Scala is also great for low-level Spark programming and easy navigation directly to the underlying source code. If you have enough experience with any statically typed programming language like Java, you can stop worrying about not using Scala at all. You will master the essential skills of the open source Apache Spark framework and the Scala programming language. Many organisations favour the speed and simplicity of Spark, which supports many application programming interfaces (APIs) available from languages such as Java, R, Python and Scala.
I am working on a project called bebe that I hope will provide the community with a secure, high-performance Scala programming interface. Scala is a powerful programming language that offers easy-to-develop features that are not available in Python. Scala offers a lot of advanced programming features, but you don't need to use any of them when writing Spark code. Its API is intended for data processing and analysis in multiple programming languages such as Java, Python and Scala.