In my experience the official software was very buggy and unreliable. Which isn't great for something about making immutable data live forever. I had bugs with silent data truncation, GC deleting live paths and the server itself just locking up and not providing anything it had to the network.

The developers always seemed focus on making new versions of the protocols with very minor changes (no more protocol buffers, move everything to CBOR) rather than actually adding new features like encryption support or making it more suitable for hosting static sites (which seems to have been on of its main niches).

It also would have been a great too for package repositories and other open source software archives. Large distros tend to have extensive mirror lists but you need to configure them, find out which ones have good performance for you and you can still only download from one mirror at a time. Decentralizing that would be very cool. Even if the average system doesn't seed any of the content the fact that anyone can just mirror the repo and downloads automatically start pulling from them was very nice. It also makes the download resilient to any official mirror going down or changing URL. The fact that there is strong content verification built in is also great. Typically software mirrors need to use additional levels of verification (like PGP signatures) to avoid trusting the mirror.

I really like the idea, and the protocol is pretty good overall. But the implementation and evolution really didn't work well in my opinion. I tried using it for a long time, offering many of my sites over it and mirroring various data. But eventually I gave up.

And maybe controversially it provided no capabilities for network separation and statistics tracking. This isn't critical for success but on entrypoint to this market is private file sharing sites. Having the option to use these things could give it a foot in the door and get a lot more people interested in development.

Hopefully the next similar protocol will come at some point, maybe it will catch on where IPFS didn't.