Is the usage of a custom class as a property in a Matlab System block a intended behaviour?

You can set a Matlab Value Class via the Simulink Dialog on a Matlab System block and call methods of the class in the stepImpl.

Since you can set it only when its attribute is Nontunable, is this a intended behavior of a Matlab System block?

function y = stepImpl(obj, varargin)
    %#codegen
    
    % obj.myClassA is a object of class ClassA
    % someCalcMethod is a Method from ClassA: ClassA.someCalcMethod()
    y = obj.myClassA.someCalcMethod(varargin{1});
end