As you start to build more in Power BI you will find that you are repeatedly using some data, repeatedly undertaking those transformations is a waste of resources, especially when there are much, much better ways of doing things. Dataflows are quick and easy and most importantly help build standardisation.
This video will take you through how to set up a Date Table in a central Power BI Workspace. Anyone you give “Viewer” access to will then is able to reuse the dataflow for their own reports.