read it, without the phone it's just a watch with healthkit tracking.
This is not correct. Although limited, it can do more than Activity and Fitness. Apple Pay, Music (to bluetooth headphones), some native app's local store (e.g. synced email) as well as some Siri requests and Messaging.
To clear up the wifi/Bluetooth link to the iPhone, it's just an AirPlay link.
The watch uses Bluetooth for low power use, then wifi if Bluetooth signal is to weak to keep the iPhone link.
The Wi-Fi/Bluetooth link is not "just an AirPlay link". AirPlay is a AV streaming protocol used to connect iOS, OS X and watchOS devices to compatible hardware to stream audio or video. It is not used between iPhone and Apple Watch to maintain a connection.
NO phone , no messages or any other communication.
When the iPhone is out of range, the Apple Watch will establish a Wi-Fi connection either to it directly, or via a router (if within range of a known Wi-Fi network). This connection can be used for some native Watch apps including Siri and Messaging.
See this videodemonstrating that my iPhone is disconnected, but my watch is connected to Wi-Fi. Note the "Disconnected from iPhone" icon at the top of the Watch face. I send an emoji from my Watch to a different iMessage account logged in on my Mac, and it is received.
Additionally, it appears that under iOS 9 and watchOS 2, this will extend to FaceTime Audio calls as well (and I assume 3rd party native apps). There is a post by 9to5Macthat demonstrates a "Continuity Calling" feature. You can see here that the Apple Watch is listed as a separate device capable of receiving the calls. It's similar to the "Text Message Forwarding" menu on iOS 8, however, Apple Watch isn't listed here (that doesn't negate the fact it can receive iMessages when out of iPhone, however).
Finally, on the new Apple Music page. Towards the bottom of the "Membership" page, it lists that the Watch can sync music from Apple Music even "when out of range of iPhone". This will be using the Apple Watch's built in Wi-Fi.
it doesn't connect on its own to any wifi network , try checking your hub ip allocations. You won't see it EVER.
Screen grabs as taken from my Apple Watch and AirPort Extreme – matching IP and DNS name. (It only connects to Wi-Fi if Bluetooth is disabled on, or out of range of, the iPhone and when in range of a known Wi-Fi network.