Yes, that Wiki page is a mess. I’ve volunteered to improve the page, so I recently started two discussions here to get community feedback and find all the missing uses of barrier=kerb and kerb=* that were not documented in the Wiki: [1], [2]. My summary of what was missing from the Wiki pages is in this post. From reading your comments, I think my understanding aligns with yours. If I’ve missed anything or you have any comments, please let me know in the thread about the Wiki page.
I updated the page for barrier=kerb with the results of those discussions yesterday, and I hope to make the agreed updates to the page for kerb=* in the coming days.