Comment by layer8

The example listed as “dissolving enum refactor” is essentially polymorphism, i.e. you could replace the match by a polymorphic method invocation on the enum. Its purpose is to decouple the point where a case distinction is established (the initial if) from the point where it is acted upon (the invocation of foo/bar). The case distinction is carried by the object (enum value in this case) or closure and need not to be reiterated at the point of invocation (if the match were replaced by polymorphic dispatch). That means that if the case distinction changes, only the point where it is established needs to be changed, not the points where the distinct actions based on it are triggered.

This is a trade-off: It can be beneficial to see the individual cases to be considered at the points where the actions are triggered, at the cost of having an additional code-level dependency on the list of individual cases.