Hasan Savran points out the overloaded nature of switch in C# 8 and later:
It works great but the break and the case syntaxes are getting duplicated, new switch syntax gets rid of the case, and the break statements. Here how this example looks like using the new switch syntax.
Click through for Hasan’s demo. Basically, this is the difference between a statement and an expression. C#’s switch keyword has historically been a statement: given some input, perform an action but do not return an output. Performing an action within the function is known as a side effect and it adds some mental overhead to the way we process things, especially as your methods get more complex and you have to keep track of more things in your mind at once.
By contrast, Hasan’s second example is switch as an expression, which is more in the F# style and an example of why I like to joke about how what you’ll find in C# vNext is what you got in F# two versions ago. An expression is an operation which takes an input and returns an output without performing any actions causing side effects along the way. This makes expressions easier to diagram and conceptualize than statements, though statements offer more flexibility, especially when you do want to take radically different actions depending on some given input.