* You can generate domains freely using pubkeys and without coordinating with other devices, therefore enabling the browser to generate new sites at-will and to fork existing sites
* Integrity checks & signatures within the protocol which enables multiple untrusted peers to 'host'. This also means the protocol scales horizontally to meet demand.
* Versioned URLs
* Protocol methods to read site listings and the revision history
* Offline writes which sync to the network asynchronously
* Standard Web APIs for reading, writing, and watching the files on Websites from the browser. This means the dat network can be used as the primary data store for apps. It's a networked data store, so you can build multi-user applications with dat and client-size JS alone.
I'm probably forgetting some. You do still need devices which provide uptime, but they can be abstracted into the background and effectively act as dumb/thin CDNs. And, if you don't want to do that, it is still possible to use your home device as the primary host, which isn't very easy with HTTP.