[village-idiot]

The point is not the branching (although it makes a good click-bait title), the point is that we can encode the branching possibilities in our type system, rather than in the permutation of values of variables we have laying around.

[throwawayish]

While it's "neat" to encode a lot of stuff into types, it also makes code comparatively very difficult to understand for almost everyone. A big part of this is that documenting type systems is even harder and the tooling is even worse than documenting regular code, at least in mainstream languages (like C++; some called me a template guru years back), and of course that many developers are simply not very experienced with complex type systems. For that reason most developers stay well within the bounds of their languages' type system; it arguably gives you code that may be more "plain" and less "smart", but also code that far more developers will be able to reason about efficiently.

[andrewprock]

Feature rich type systems are really great if you have a good understanding of your types. Often, you don't. One of the best parts of software is it's malleability. Pushing business logic up into types makes it less malleable.

[nightski]

Types don't force you to have a concrete understanding of the problem (although they can help think about it). They help you make concrete decisions about your solution. This can save time when changing things often.