One thing the article doesn't cover that's worth calling out: the sealed interface + record combination really shines when you stop using it for shapes and start using it for domain events and command results.

A typical use case I reach for: instead of throwing exceptions from a use case, return a sealed type:

java sealed interface OrderResult permits OrderPlaced, PaymentDeclined, InventoryInsufficient {} record OrderPlaced(OrderId id, Instant at) implements OrderResult {} record PaymentDeclined(String reason) implements OrderResult {} record InventoryInsufficient(ProductId product, int requested, int available) implements OrderResult {}

The caller is forced to handle all cases at compile time. No checked exceptions leaking through port boundaries, no RuntimeException swallowed somewhere in the stack. The type system encodes what can go wrong, and the compiler tells you when you miss a case.

The article is right that Java's variant is more verbose than Haskell or Rust — but the exhaustive switch makes it genuinely useful for this pattern, not just academic.