Which is an interesting choice: Give a noose for developers to hang themselves with for every single other type other than enums – the types they are going to use most often – and not think twice, but then go full on helicopter parent when using enums – the one type that isn't particularly interesting.
It's a neat parlour trick, don't get me wrong, but I guess that's why almost all of the popular statically typed languages since Pascal (C, C++[1], Typescript[2], etc.) didn't bother with closed enums. They put their time into features that actually mattered to developers instead.
[1] Added later in life, granted.
[2] Ironically, does support value constraints except in the case of using enum.
