Huge respect all around; we are heroes together. I offer my perspective re-affirming there are other perspectives (on this large topic in our relational database). With the simple diagram, we use color as blue and green to distinguish different syntax as differing objects, tagged similarly. Everybody can agree to it. It pedagogically rocks; crackle-boom.
Now, simultaneously, a pink landuse thing is going on, too (we render its edges and boundaries, we model with signals and edges of ways in OSM…). Not either-or, this is both. Pink AND blue; blue AND green. Yellow as a visual relation call-out. As simultaneous differing concepts. Sometimes syntax shares across things, like railway. A deeper diagram visually groups in geometry and logic as syntax with color. Boom.
The ? is there to denote that the area: prefix, while it exists, is a meta-syntactic method to call out something exceptional or at least different. I see how both can and do exist. There isn’t always a pure “this method is always correct.” With these diagrams and bouncing back to further wiki if need be and brief wiki pointing back here, OSM draws a certain-sized box around this (snapshot for now). As two pretty diagrams in our wiki, with some links back here many might say captures 99% or 100% of the spirit. If we must put a number on it. I nod my head.
For now. I call it a wrap!