Requiring all properties of an @Observable class to have default values feels pretty clunky in practice.
Until that requirement is relaxed I think I would still prefer to use a generic store type with an hand-written Observable conformance. Thankfully they mention relaxing that constraint in future directions of the proposal—hoping that comes soon.
https://github.com/apple/swift-evolution/blob/main/proposals/0395-observability.md#initializers