If you know Swift or Java, C# is trivial to pick up. And Xamarin's SDK maps closely to their native counterparts, so hardly anything new there either. I'd say

If you know Swift or Java, C# is trivial to pick up. And Xamarin's SDK maps closely to their native counterparts, so hardly anything new there either. I'd say C# is worth learning if you have the opportunity. But agree it's better to invest time learning a specific platform like iOS or Android. Coupled with C#, you'll be in good shape to pick up any Xamarin project out there.