His example of a function which is unreadable, is pretty typical. It still might be slower than a tight loop in C, but it’s only unreadable the first time you write something like that.
I admit I recognized only some general NumPy things like masks, unique, reductions, outer etc: I don’t use Pandas and not sure what the non-Numpy stuff does.
I still don’t think it’s more obscure than equivalent for loops or FP folds or similar.
That said, Numba would be a natural tool here.