If you just want to count cell values, you don't have to select a cell attribute. The other functions like sum and average can only operate on numeric values.
What do you want to achieve?
Actually not a true pivot table, but still an interesting use case for a dynamic table.
I can add action display, which shows the value(s) that exist at a given combination of entities A and B
This does come with a few restrictions:
Would that work for you?
Edit: New release is on GitHub: https://github.com/synobsys/mendix-PivotTableWidget/releases/tag/v2.2
Added display action and styling based on the displayed value. Useful for enums.
I also submitted it to the appstore. But I expect that will take a couple of days to get approved,