In my opinion and from the comments I think that encoding one state is not a problem either in C# or F#. Now assume we have to add an additional state to a user

In my opinion and from the comments I think that encoding one state is not a problem either in C# or F#. Now assume we have to add an additional state to a user and all proposed subclassing solutions in C# turn out to be what they are: not optimal. My biggest problem with OO is, that it only allows us to structure code in a one dimensional way (inheritance) but in reality we will face more complex scenarios. and even this way is increasingly discouraged: composition over inheritance...