Pie charts are great to use when you want to show comparison, as they show the parts-to-whole relationship. For example, if you want to see the country of registration of players registered the last 30 days. With a pie chart, you could easily identify which nationality has had the highest registration engagement.
There's only one way we recommend to use a pie chart, and that is when you want to have 1 measure and 1 dimension. Also, recommended to use a measure with fewer values.
In the above pie chart, we can see the split between which players are using which currency. Each currency is represented by a slice with a specific colour and the size of the slice reflects how big the value is. The bigger the slice, the higher value it has. Worth noting is that the slice size represents the percentage of the whole value of the measure.
This means that the measure [Count] is represented by the size of each pie chart, whilst the dimension is represented by the number of slices in the pie.
So, looking at this chart we can see that the most common currency amongst the player base is by far GBP (almost half of the players have this currency), followed by EUR and then SEK.