To me it feels very similar to an interface (trait) implemented by a bunch of classes (structs). I have multiple times wondered which of those two approaches would be better in a given situation, often wanting some aspects of both.
Being able to exhaustively pattern match is nice. But being able to define my classes in different places is also nice. And being able to define methods on the classes is nice. And defining a function that will only accept particular variant is nice.
From my perspective a discriminant vs a vtable pointer is a boring implementation detail the compiler should just figure out for me based on what would be more optimal in a given situation.
This is possible to achieve (or hack your way through, if you will) by parameterizing the type and using a nullary type (a type which is impossible to have) to exclude specific cases of a sum type. In Haskell this would look like this:
data Weather a b c = Sunny a | Rainy b | Snowy c
-- can't snow in the summer!
onlySummerWeather :: forall a b. Weather a b Void -> String
onlySummerWeather weather = case weather of
Sunny _ -> "Got sunny weather"
Rainy _ -> "Got rainy weather"
Snowy v -> absurd v
Personally I find we work way too many hours. We spend the good part of 5 days a week (if we're lucky) at work, often literally all the daylight hours, at least in winter. I have to take my daughter very early in the morning to the nursery, then I can't see her until the evening.
I want to believe that future generations will look back and find this unconceivable, and I hope AI shows us the way.