About the default constructor for Grid

Consider the default constructor for Grid:

def __init__(
        self,
        multi_index: MultiIndexSet,
        generating_points: Optional[ARRAY] = None,
        generating_values: Optional[ARRAY] = None,
    ):

I'm wondering what's the purpose of optionally specifying both the generating points and the generating values? Because generating points and values are typically related (generating points are created from generating values), is there a case where the two are different?

Furthermore, I think the interface is also incosistent because if one specifies the generating point then they must also specify the generating values because otherwise it won't be generated automatically (so not optional at all).