Why does MATLAB set the Method Attributes of built-in methods to 'Hidden'?

'empty' is matlab built-in method."At the bottom of the documentation page, it is mentioned: 'empty is a hidden, public, static method of all nonabstract MATLAB® classes.''

There is a question, if user build a classes method,for certain reasons, users may want to set a class method as 'Hidden' to prevent others from seeing it. However, in the case of MATLAB built-in methods, everyone is aware of their existence. So, what's the purpose of MATLAB setting the Attributes of this method as 'Hidden'?"

If you input mc=?SubClass in command line and open mc-->MethodList in workspace,you will find two method, one is 'SubClass' ,another is 'empty'.In fact, the 'empty' method isn't completely hidden, so what's the significance of setting a built-in method to 'Hidden'?"

classdef  SubClass < Base
    methods
        function obj=SubClass(value)
            obj=obj@Base(value);
        end
    end
end

classdef Base
    properties(Access=private)
        a;
    end
    methods
        function obj=Base(value)
            obj.a=value;
        end
    end
    methods (Access=private)
        function Fun(obj)
            disp(num2str(obj.a));
        end
    end
end