Its always nice to work through the updates by relating them to something you are working on.
Lets have a look at the Gradient Legends
lets start with a simple events chart for 2020
the Measure is
Number of Events = DISTINCTCOUNT('Event Metrics'[Event Id])
So Now lets colour the columns based on number of Events from Last year
LY Events = CALCULATE([Number of Events],SAMEPERIODLASTYEAR('Date'[Date]))
This is great because we now get an idea of how different last year was, But without any legend information its quite difficult to understand the new information
Lets add a legend
Here is where the 2020 updates come into play. we can now see that the colour is related to Last year events and it goes from 0.9K up to 1.2 K so we can see that in 2019 July had the highest number of Events.
(I have set the colour to red because in the context of our report, More events isnt actually a good thing)
Just remember, you cant add a legend data item into your visual if you are going to do this, but this is a really great new feature