Most developers use Power BI desktop to design the visuals and publish to the service for production.
Out of the box, Power BI has 29 visuals. There are 208 custom visuals that can be down loaded from Appsource.Microsoft.com.
While there are many choices, the business problem might not have a visual that can be customized the way you want. How do you solve this problem?
This is where custom scripting with Python comes in.
At the end of the presentation you will know which libraries that you can use to extend your toolbox for both on premise and the azure service.