This means that announces are much more likely to be transferred over the faster medium first, resulting in paths that are on average the most reasonable balance between speed and distance.
If that doesn’t make sense at first, I get it. I find trying to visualize how it works really helps. Reticulum is conceptually so different from anything else out there that it takes a while to understand.
See http://reticulum.network/manual/understanding.html#the-annou... for more details.