Currently it also already possible to add the same measure multiple times in a chart but then use different aggregations (average, median, max, min)
Another typical use case is to add comparison values from a timing perspective.
For example: A column chart showing the Process cycle time by country for the current reporting period (e.g last week) and the previous reporting period (last week -1) or current reporting period and previous 3 reporting periods (last week -1, -2, -3)
Additionally another comparison value used very frequently is the year-to-date. Of course this is typically used in a line chart with dates.