I find the OCAML-inspired option types in F# and Scala more aesthetically pleasing but the author mentions in a previous post why C# wouldn't implement them.
Some features (Async streams, indexers, ranges and Default interface members) won't be available in .Net 4.8, only .Net Standard 2.1.
The post appears to hint that you can polyfill some of the types yourself.
> As always, the C# compiler is quite lenient about the types it depends on. If it can find types with the right names and shapes, it is happy to target them