Well Apple Pay, running/tracking apps and listening to music via Bluetooth all work without phone. And I don’t have the model with internal sim, maybe more stuff works with that version.
I agree you need the phone too, but at least I’ve been able to track a run while listening to music on my headphones and pay for water after my flask broke all without a phone present.
I think we’re close to just the watch but I’d be damned if I want to dictate messages etc. The screen size and lack of input devices definitely holds it back from being genuinely standalone.