> The one tiny drawback is that the globals have to be variables instead of constants, but that’s one of those problems that really only exists in the theoretical realm.

I'd argue that needing this enums safety so bad that you go out of your way to create a struct with a protected field also lies in the same category of something you need that is mostly in the theoretical realm too.

Don't get me wrong, sometimes you want that kind of protection indeed and it's easy to mess up if you need to add validation everywhere. However, most times you can get away with just rethinking your code.

More importantly, I think the downside of using variables rather than constants makes it less safe than the alternative of relying on you always having to do validation.