I'm at the point where I can no longer see any reason to use UTF-16. UTF-8 is used everywhere today and constantly converting between the two is not only inefficient, but also introduce a risk of bugs/corruption.
Yes it’s annoying that we’re stuck with UTF-16 inside many programming languages. Still, I think it’s better than having two types of string (C, C++) or introducing a breaking change (looking at you Python 3).