It's not incorrect to say that hashes and signatures add some overhead, but the question is whether the overhead is significant enough to matter for the usecase. Probably not.

Dat is realtime. You are notified about updates as soon as they are distributed. In Beaker, the files-archive API has a `watch()` method to do this. If you're accessing a dat files-archive, you're participating in the syncing swarm and so you'll receive those updates automatically.

You'll want to use a UDP socket if you're streaming a high volume of data with low latency requirements, for instance for a multiplayer FPS. But Dat has been used to stream live video, so it's probably real-time enough for most Web use-cases.

Small aside: Comparing Dat to CRDTs is apples to oranges. It's like comparing Javascript to B-Trees; they're not quite the same kind of technology. In fact, the new version of Dat uses CRDTs in order to allow multiple users to write to a files-archive.