Quote from documentation:

TableModelColumn supports all of Qt's roles, with the exception of Qt::InitialSortOrderRole.

If I try to use e.g. 

TableModelColumn { display: "checked"; decoration: "fruitType" } 

I get log messages like: 
QML TableModel: setData(): no role named decoration at column index 1. The available roles for that column are: QList("display")

This used to work but as I haven't noticed this until using 6.6.x so I cannot say which version introduced this change.