> Thus, in such languages, there shouldn't be a conceptual or syntactical difference between values and references. The fact that C# allows to differentiate them from each other is a leaky abstraction imho, built in to satifsy people form a C/C++ background.

It's not a leaky abstraction, it's a very specific design choice for performance reasons. Java also has this dichotomy between types, and for the same reason, although I believe they only delineate between primitive/non-primitive.