User-story-focused validation
Enforce complex, multi-field invariants that keep a domain entity from ever entering an invalid state - not just isolated per-field checks.
Event-driven lifecycle
Subscribe to creation, update and deletion lifecycles at both the entity and individual field level with onSuccess, onFailure and onDelete handlers.
TypeScript & Rust, one model
The same constant, dependent, lax, required and virtual field concepts apply in both implementations, so switching languages doesn't mean relearning the mental model.