To my mind, a language where creating a class, then passing it to be used in a background thread is 'hard and sometimes impossible' is a very badly designed language.
The practical impact is that it just pushes devs to do everything on the main thread - which is obviously a fail.
Considering NSImage a special case chimes well with how I percieve the development of Swift.
It's obviously a central class for anyone developing anything real on MacOS. But the 'science project' that is modern swift evolution doesn't seem to consider real usage important.
To be fair - using sending and enabling RBI has fixed this issue for me.
Two undocumented swift features...