I also found the style in this article kind of annoying and difficult to follow, but I think "discovery fiction" usually means something different. The two examples Michael Nielsen gives are https://michaelnielsen.org/ddi/how-the-bitcoin-protocol-actu... and https://michaelnielsen.org/ddi/why-bloom-filters-work-the-wa.... Another classic example is http://blog.sigfpe.com/2006/08/you-could-have-invented-monad....

You can see there's no dialogue; the idea is to frame an article as "how might you discover/invent this concept on your own", rather than just directly explaining how a thing works. You are given a fictional goal, and you "discover" the subject matter by building iterative solutions.