Oh are you intimately familiar with Atlassian's systems?
Marketplace is Atlassian Marketplace, a real website, REST API and bunch of frontend components. If it's not part of an architecture, what is it?
I did simplify Commerce, the system is Atlassian Commerce Cloud Platform. I apologise that I simplified the name for an example, which has confused you.
The problem is that people are munging architecture, data flow, and process into one diagram.
"Marketplace" isn't part of an architecture. "Commerce" isn't an architecture part. It's a functional piece.
Revamping how architecture diagrams are made won't fix incorrect ways of describing architecture.