Exactly. One can think of examples where these cases make sense, but there are many more examples where there are more cases (e.g. there many be multiple kinds

Exactly. One can think of examples where these cases make sense, but there are many more examples where there are more cases (e.g. there many be multiple kinds of partial successes) or fewer (most functions, which either succeed or fail.) Also, the design requires null values. A point which the replies have ignored.