DAX is an acronym for Data Analysis Expressions. If are familiar with Power Pivot for Excel. And or SQL Server Analysis Services Tabular (SSAS Tabular). Then you are conversant with DAX. In a way, you could compare DAX as Excel on steroids.
DAX is Microsoft Power BI chosen programming language. DAX unlocks powerful capabilities. Such as select, join, filter, enabling data to be dynamic manipulated.
What this means?
Users can interrogate a dashboard to dynamically acquire an answer to their questions.
Should you Bother to Learn DAX?
The pareto principle or 80/20 rule states that 80% of the result can be achieved with 20% of the effort and vice versa. Some will say without DAX 80% of what many users require from a dashboard cannot be executed.
Power BI is a powerful tool, even beginners can create useful dashboards and insights. Many dashboard requirements are simple. Such a dashboard can be built without extensive coding.
Of course, more advanced dashboards will require DAX. For example, multiple dashboards. May require numerous columns and or measures to be able to generate the required output. Using DAX can limit the number of calls for data. This can help to ensure dashboard performance for users is acceptable.
What this means for many Power BI users?
The investment in learning DAX may not be a good return on their time. Besides in today’s world of freelancing platforms. 24/7 connectivity and digital nomads. It might be easier to just outsource the DAX part of your dashboard to a professional.
BUT should you learn DAX?
You do not need to become a DAX guru. Most citizen developers can quite comfortably. Get by with a rudimentary knowledge of DAX. Learning DAX can be a steep learning curve. even so the benefits may return a very good investment on your time.
Is there alternative?
Yes, you can achieve a lot with R or Python. For example, adding some new extra columns to your dashboard can be done with Python.
Where can you learn DAX
Learning DAX requires time and effort however you do not need a Phd in computer science. Naturally, there are numerous paid courses. But you do not need to pay. There is a wealth of free online training, documentation, videos, communities.