I'd encourage you to learn another language to learn programming basics. The chosen language doesn't matter a whole lot. What you need are the concepts. All languages essentially do the same basic things, only the details differ.
JSL is a great language for automation and very good for writing code you need to distribute and support. If you follow good practices, writing robust reusable code is pretty easy. You can get JSL to do nearly anything you desire. I definitely consider JMP with JSL a stable runtime environment which can be used as a serious development tool for complex and long analyses, extensive data manipulation, and extensive data perparation.
Where things will get painful at times is in the lack of a good debug tool, cryptic and sometimes misleading error messages, and the inability to call subprograms which are fully isolated from the calling program. Access to many low-level system comands and bit-level commands is missing, but JSL supplies ways to get around that too.