Discussion of nullability is definitely an important omission here. Part of the issue is that Pandas itself supports multiple flavors of "nullability", e.g. the

Discussion of nullability is definitely an important omission here. Part of the issue is that Pandas itself supports multiple flavors of "nullability", e.g. the old NaN hack for Numpy float dtypes and None for object dtype. It is the way it is for good historical reasons, but now that we have proper nullable dtypes, the existence of these special cases only increases the importance of a coherent design going forward.