I read that it makes things faster ( https://developer.xamarin.com/guides/xamarin-forms/xaml/xamlc/
and converts it to IL.
What it does not seem to do is check that the variables used in XAML are actually in the code. I had the wrong case on a variable and it took quite some time to find the problem. However, just in case I have not set up XAML compilation correctly, how can I tell that it is actually happening?