The really interesting part for me is what this technology might lead towards in the end, which is decentralized community based curation. An index with white listed curation would be indistinguishable from a website, but it would not need a domain name nor a ip address to function.
The problem with decentralised software is that you don't want to host other people's illegal content. I once tried out zeronet, which downloads the entire decentralised website and anyone can post things to it. Although I have not found CSAM directly on their Reddit equivalent, there are people posting advertisements to zeronet CSAM sites. The idea that I am downloading and automatically redistributing content like that is disturbing and zeronet is dead for a good reason. It's a pool that is asking to be peed in, even if the abusers themselves are a tiny minority.
Bitmagnet may download metadata about CSAM content, which is automatically deleted with fairly high accuracy. You would never be redistributing it. No outgoing peer protocol is currently implemented. This is planned but it will give users control of what they're sharing rather than indiscriminately sharing everything.
https://www.coveapp.info/ approaches this in a similar fashion. I don't believe there's any legal issues in collecting metadata in an automated fashion from a public network. So creating a search index for personal use from this is fine. However if you do click and start seeding questionable content, then it becomes an issue. https://www.coveapp.info/#dht-indexer
