Yep, I think #[2] informed me too saying that it only works when Damus is installed on the phone.
I think this is a useful and cool feature. Maybe later when `nostr:` URI's are supported clients could be invoked with `https://webclient.com/p/npub...` or maybe even now conditionally invoked if Damus app is not found, to launch `https://damus.io/p/npub...` to open snort.social maybe.
Just a thought.