I find the network and addressing model to be the worst designed and least interesting part of Urbit. That's the part that reflects Yarvin's political ideology, but I also think neoreaction is political flat Eartherism. Pretty much all of neoreaction boils down to refusing to account for survivorship bias. The average old thing looks better than the average new thing because crappy old things were forgotten.
The interesting parts are the functional programming approach used, which is somewhat novel or at least novel in its execution.
Another reply compared it to DNS, which is valid, but DNS does not have artificial limitations like Urbit does. DNS is also in many ways a bad design, not because it's inefficient but precisely because it encourages a feudal model that artificially constrains what the Internet could do. DNS was maybe the only viable model back when the largest machines online came with a whopping few megabytes of RAM, but some kind of distributed replication approach could be done today.