The reason I found them useless is that the suggestions were too specialised. I usually do not want to watch a dozen videos on the same topic. I usually want to watch one high quality video about it, then move on. Same with channels. I do not want to follow ten channels about each of my hobbies. One channel or two high quality ones is enough.
So, even though the linked project is super cool from a technical perspective, I am not sure how the algorithm could be improved to attend to my taste.
[0]: https://hakon.gylterud.net/tutorials/youtube.html (YouTube self-defence)