You couldn't redistribute NGen'd binaries tho, it was basically a local AOT'd cache.
As far as Native AOT, last I checked it requires trimming which breaks WinForms (and WPF) according to the official docs.
I don't think this matters much, though. There's simply no practical reason to AOT-compile a WinForms app. Not when the framework is guaranteed to be there, and JIT compiler is plenty fast.
Then there is .NET Native and Native AOT.