Today in OOTB, it looks like editing Attribute Values of Variant Items is not allowed. It’s even explicitly set in item.js where it mentions below in line 752.
// value column is displayed but not editable
grid.set_column_disp("attribute_value", true);
grid.toggle_enable("attribute_value", false);
Any reason why this is the case? Does anyone know how to make it editable safely?