Ya - No - I get what you're saying, and the text is accurate, the visual rendering looses a pattern that should make it eaiser to see and understand the system as a whole. If we use a <--> connector the alignment of UI -> API -> Data in 3 columns looks right and the arrow-head on the BUS side is hidden by all the other arrows connecting inbound there.

If we want arrows to represent network connections, all arrows should go from bus to database. If we are using arrows to represent flow of data, then mongo database collections will sources, and elastic is a sink. This diagram is supposed to "look good" - the technical aspects of sources and sinks is in the architecture.yaml file. That probably does need to be updated, but I haven't looked at it in quite a while.