Even without that, returning a "foo" that has to be explicitly unwrapped makes for a safer API than having "foo" be sometimes a valid result and sometimes silently an error instead.
I think single entry/single exit is very valuable, and worth a bit of clunkiness for. And the branch version is also pretty clunky: either the long-winded "return ", abuse of "and"/"or", or the weirdly backwards expression version of "if" that Python has.
I don't disagree that branching on bits is clunky. That it's still less clunky than using Church or Scott-encodings speaks volumes of the practicality of the latter.
