[Question] What confusions do people have about simulacrum levels?

I’ve noticed comments to effect of “simulacrum levels seem very confusing”. Personally, simulacrum levels seem fairly obvious-in-retrospect and self-expanatory to me, based on a handful of explanations and examples from Benquo and Zvi’s posts. I’m not sure whether I’m missing something (in which case I should figure out what), or whether I have some pre-existing frame which makes it all more natural (in which case I should figure out what that frame is and try to communicate it), or whether this is just about happening to read the right posts in the right order. So… what are some things people find confusing about simulacrum levels?