Currently it is just another language - for me one of the real compelling cases of working with .NET was the absolutely god-tier integration of tooling for creation UI kits (that is aside from the very good case that C# is a language that is superior to anything else I've professionally worked with, that's not an argument that will sway anyone). Such an argument doesn't exist for .NET core, because it suffers from the same problem as every other contender: Creating a cross-platform GUI is an absolute cancer and is by far the biggest problem you'll have writing code. That being the case, why switch?