Yup. Calling it. This is the future, may not seem like it to everyone but this is a part of actually new and extremely useful, passively scalable technology. Imagine (good) unkillable zombie databases- so long as the name of a piece of data is known (its hash).. someone, somewhere, might make it possible for you to answer your query, without even needing to setup a server setup.. that’s _it_! Not to mention it might…
Unfortunately this is still killable. Someone needs to periodically publish up to date databases using some outside protocol. Also if you participate in the public DHT, then your participation is public and can have consequences on your real-life legal entity. If you want to use TOR and onion sites, I don't think this really adds anything to those. I think this just helps you optionaly crowdsource bandwidth.
You don't expose your data layer directly to the consumer, you expose an api that will resolve to one, two or several databases from one or many peers. The indirection allow you to define your rules and use your data layer in a way that fits your application goals in the best way possible.
So whats is immutable is your application, api and initial data, which you can mutate at later stages through other torrents or by consuming other api's from other peers and mutating your initial database state.
The problem is, the current browser is not meant for this, Javascript is not meant for bigger and complex applications (of course you can do it, but..)