I read through your whole readme and I still am not able to answer the question: "what kind of project would I use GUN for?"

or, even, "what is gun replacing?"

I mean, it looks interesting and I would like to play around with it, but I don't understand enough to know what kind of stuff I can build with it.

I tried several times to understand what GUNdb does and how its different or which features it has. I have given up. As far as I can tell it is something between Blockchain, graph-database and sync.

I also tried to understand the codebase which is impossible with obfuscated code like this one: https://github.com/amark/gun/blob/master/lib/store.js#L16

Thunderbong's answer is spot on (it replaces Firebase).

Here is a 5min interactive coding tutorial that shows that using GUN is more powerful than reading about GUN. https://gun.eco/docs/Todo-Dapp

For instance, Archive integrated in 1 week.

Notabug first version was built in 1 week with it. (p2p Reddit)

Organization can go a far ways in a short time.

Gun is essentially similar to Firebase[0]

I've used it in some projects and found it useful. Thanks.

[0]: https://firebase.google.com/