This video introduced new features in Power BI that have been added in 2018 and that are relevant to the DAX and the Data Model section of the course.
Quick Measures allow users to build more complex DAX measures from a set of built-in templates, which means that you can create many more calculations without learning DAX. It’s also a great way to learn DAX because you can study the definitions of the calculations that are created.
What-if parameters also create calculations (a measure and a calculated table) for you automatically, along with a slicer. They allow you to implement a very common pattern in Power BI which allows an end user of the report to select different numeric values with a slicer which are then fed into a calculation. For example, it can be used to allow an end user to select a different tax rate and see what impact different tax rates have on other figures in a report.