I find it difficult to understand the difference between calculated columns and measures.
The main difference is that calculated columns consume more memory, and they are basically columns that we add on top of the existing datasets inside Power BI. They are useful for things such as changing names inside columns, adding attributes and etc. Measures are designed to perform calculations and they are executed only when they are called for. Imagine having a measure for sum of all sales. It won’t run unless you have a visual inside Power BI that calls for that measure. If you have a calculated column on the other hand, it will run each time you open the Power BI file.